1 Introduction

For the scientific and metrological infrastructure of any country, metrological standards and related activities are essentially required. Metrology plays a central role as an engine of industrial revolution and inclusive growth. It plays a vital role in support of the sustainable development because metrology is essential to protect the planet, ensure the dignified and quality lives for all people, and attain wide-ranging economic growth and opulence. It is a primary pillar for trade, scientific research, novelty and promising technologies, technical collaboration, or even simple exchange of information [1,2,3]. For the scientific and industrial advancement of any nation, the NMs play significant and unique role in the progression of metrological fields and associated technologies. Each nation requires a strong metrology scheme in place to provide the metrological traceability to stakeholders in each of segment of the economy. This exercise is obvious for maintaining the parity in all the measurements to attain sustainable developments at various front like science, engineering, technology, industry, commerce, business trade, etc., which eventually enables to accomplish the goal of self-reliance. It is also requisite for the NMIs world over to constantly upgrade and maintain their measurement systems at par with the other NMIs and as per the new technological advancement and challenges arising in the international scenario.

The CSIR-NPL, being NMI of India, is also playing exceptional role since its inception on January 04, 1947, taking the metrology field to masses through its invaluable metrological services to stakeholders; educational, awareness, training and academic activities and campaign for students, industry, academicians, policy makers, regulators, etc., and providing time to time need-based solutions, services, technologies and advises to all the stakeholders and government agencies etc. Recently, CSIR-NPL has celebrated its 75th Foundation Day, which was attended and graced by a galaxy of political and science leaders. In order to commemorate its glorious journey of 74 years, it was considered appropriate to make a concise go over of the events which eventually resulted in the formation of this wonderful leading laboratory of the country; its major accomplishments of national and international relevance; excerpts of inspiring and motivating speeches/messages of some of the eminent political and science leaders, specially the most stirring peroration of Honourable Prime Minister of India Mr. Narendra Modi; and the summary of various activities held during National Metrology Conclave (NMC-2021) organised on the Platinum Jubilee Foundation Day, i.e. January 04, 2021. The CSIR-NPL has not only been playing its primary role of establishing and disseminating the national measurement standards in the country, but also formulates and advises the India specific policies, guidelines and gives recommendations on evolving advanced metrology programmes for the government organizations, institutions, regulators, industries and other stakeholders. It is also helping Bureau of Indian Standards (BIS) and Department of Legal Metrology in the formulation of written standards and assisting National Accreditation for Calibration and Testing Laboratories (NABL) in many ways in accreditation of calibration and testing laboratories. We hope that the brief reassess thus published as a feature article would be useful for the readers involved/interested in metrological activities as a historical and up to date source of information.

2 Historical Aspects

Historically, metrology is not a new concept in India and it dates back to ancient times. However, with times, era, civilization, culture and geographical areas, the uses, types and names of the standards, units, measurement techniques, etc., continued to change [4,5,6,7,8]. The Harappa civilization, which is considered one of the highly developed civilizations (about 5000 years old), had witnessed several admirable examples of developed dwellings and township having planning and architecture, which would have not been possible without metrology [4, 5]. The identical size of the bricks used in the structure is one of the beautiful examples. Around 2400 years ago, there existed a distinct system of weights and measures in the Maurya era [4,5,6,7]. Later on in the Mughal era, the emperor Akbar had introduced a unit of length ‘guz’, which was widely used [4, 8]. It is still in use in countryside even after the introduction of the metric system in India in 1956. Illustrations of the equal arm balances found in the art of Ajanta cave and beams of steelyard balances are other beautiful examples, which were discovered during eighth century. Some of these examples evident that the measurement system is an integral part of each civilization/era.

2.1 Creation and Establishment of Scientific Institutions Responsible for Metrological Activities

The Railway Board established the National Test House (NTH), formerly known as the Government Test House (GTH) in the Kolkata (then Calcutta) in 1912 to fulfil the requirements of the Indian Railways as import substitution. The Indian Industrial Commission (IIC) recommended for the formation of an Indian Stores Department (ISD) during the year 1916–1918. Later on, the NTH was merged with ISD for doing regular testing of the general stores of the Government Departments including defense for a long time. During the year 1934, Government of India formed the Industrial Intelligence and Research Bureau (IIRB), which later on renamed as Industrial Research Bureau (IRB), which is the origin of the present CSIR. The IRB formed and nurtured in NTH for conducting the Research and Development (R&D) for the indigenous development of raw materials [9].

During British era before independence, the Institution of Engineers (India) (ISEI), situated in Calcutta was given the mammoth task giving recommendations for building up the industrial infrastructure in the country and the ISEI had prepared the first draft of the constitution of an institution which could take up the task of formulation of National Standards. This leads to the establishment of Indian Standards Institution (ISI) through a memorandum issued on September 03, 1946, by the Department of Industries and Supplies. The ISI finally came into existence on the January 06, 1947. The ISI became Bureau of Indian standards (BIS) on April 01, 1987 through an act of parliament dated November 26, 1986. Through this change over, the Government aimed to building a quality infrastructure, awareness and more participation of stakeholders in the formulation and implementation of the national standards [9].

In order to initiate, a laboratory accreditation program in India and provide the accreditation services to the testing and the calibration laboratories, the Department of Science & Technology (DST), Government of India, in the year 1982 set up the National Coordination of Testing & Calibration Facilities (NCTCF). The NCTCF started providing accreditation to testing and calibration laboratories with the cooperation of CSIR-NPL (NMI of India) as well as having its office in CSIR-NPL. Subsequently in 1993, the NCTCF was renamed as National Accreditation Board for Testing and Calibration Laboratories (NABL). The NABL was registered under society Act on August 12, 1998, with the objective of maintenance, implementation, promotion, guidance, coordination, etc., of an accreditation system for laboratories. In the year 2017, NABL merged with Quality Council of India (QCI) [10, 11].

2.2 Establishment of CSIR-NPL

The Government of India through Legislative Assembly recommended the objectives of CSIR, New Delhi, on November 14, 1941, for the purpose of fostering industrial development in the country. The CSIR was established on September 26, 1942, under the leadership of Sir Shanti Swarup Bhatnagar. In the year 1943, the governing body of CSIR decided to establish 5 national laboratories—National Physical Laboratory (NPL), National Chemical Laboratory (NCL), National Metallurgical Laboratory (NML), Central Fuel Research Institute (CFRI; now CIMFR) and Central Glass & Silicate Research Institute (CGSRI; now CGCRI) [9, 12,13,14]. One of the objectives in the CSIR-Bye Laws—2018, Para 2, (b)-vii clearly stipulates the need of “maintenance of national physical standards and a library of standard reference materials” [14]. Keeping in view the importance of NMI in the socio-economic and industrial growth of the country, our former visionary leaders worked hard for establishing the CSIR-NPL to work for the establishment, custody, maintenance, upgradation of national standards of measurements, primary standards linking them to SI units and other standards in terms of derived units. Historically, the foundation of CSIR-NPL was laid down exactly 74 years ago on January 04, 1947, before India became independent by Pandit Jawaharlal Nehru, then Vice President of Interim Government of India. The former Deputy Prime Minister Sardar Vallabhbhai Patel formally opened it on January 21, 1950. During this period, India didn’t have the statutory acceptance from the International Bureau of Weights and Measures (BIPM) as well as well-equipped laboratory to take-up the measurement standards activities [15, 16].

2.3 Legal Identity, Framework and International Linkages

The Government of India enacted the “Standards of Weights and Measures Act” for the first time in 1956 to ensure that every citizen has an access to uniform standards of weights and measures those are traceable to the SI units [17]. During the year 1957, India became member of the General Conference of Weight and Measures (CGPM), BIPM, an International Intergovernmental organisation constituted by diplomatic treaty, i.e. ‘The Metre Convention’. Being NMI of India and to fulfil the mandate, Dr. K. S. Krishnan, the then Director, CSIR-NPL signed the ‘Metre Convention’ on behalf of Government of India in the year 1957 (Fig. 1) [18]. Subsequently in the year 1957, BIPM provided CSIR-NPL the Copies No. 57 and No. 4 of International Prototypes of the Kilogram (IPK) and the platinum-iridium (Pt–Ir) Metre bar, respectively, to realize the SI base units ‘kilogram’ and ‘metre’[9]. This was the milestone in the foundation of quality infrastructure in independent India.

Fig. 1
figure 1

Republic of India became member of the CGPM in 1957 and currently represents in 3 Consultative Committees (CCEM, CCM and CCTF) of CIPM. India also signed the CIPM MRA in 1999 and was authorised to use CIPM MRA logo on calibration certificates in 2007

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The Standards of Weights and Measures Act was subsequently amended in years 1976 and 1987. The current version of The Legal Metrology Act, 2009 was issued on January 14, 2010, and subsequently The Legal Metrology (National Standards) Rules, 2011 was issued on January 7, 2011 (The Gazette of India: Extraordinary, Part II-Sec3(i) [17]. The use of the national prototype of the metre, was discontinued after the establishment of laser-based primary length standard as national standard of length. However, the national prototype of the kilogram is still in use as national standard of mass. Recently, the Ministry of Environment, Forest and Climate Change (MoEFCC), Government of India, has designated CSIR-NPL as a national agency responsible for carrying out the certification for the instruments and the equipments for monitoring emissions and ambient air through a gazette notification issued on August 22, 2019, under Section 3 of the Environment Protection Act, giving CSIR-NPL the authority to certify instruments [19].

In the year 1977, the Commonwealth Science Council (CSC) and the CSIR-NPL along with 9 Commonwealth countries formed a cooperation whose main objective was to form a Regional Metrology Programme of joint projects to link each National Measurement System into a collaborative network, which later on became Asia Pacific Metrology Program (APMP) [20]. The APMP presently comprises of 45 full members. India signed the International Committee on Weights and Measures Mutual Recognition Arrangement (CIPM MRA) in 1999 and CSIR-NPL initiated the implementation of Quality Management System (QMS) based on the international standard ISO/IEC 17025 to establish the international measurement equivalences for barrier-free trade [18]. The CIPM MRA responses to the growing need for an open, transparent and comprehensive system to give users reliable and quantitative information on the compatibility of national metrology services and to provide technical basis for the wider agreement for the international trade, commerce and regulatory affairs. CSIR-NPL has been maintaining the quality system based on ISO/IEC 17025 for the various parameters under Physico-Mechanical, Electrical and Electronic standards since 2003. The BIPM has authorised CSIR-NPL to use CIPM MRA logo on the calibration certificates issued by it within the currently approved 236 CMCs registered in KCDB of BIPM (Fig. 1). The calibration activities in these areas have been peer-reviewed during 2003–06, 2009–11 and further under the peer review process during 2020–2022 to fulfil the requirements of the CIPM MRA.

2.4 Adoption of Redefined SI Units

Recently, in a landmark and historic decision, the ground breaking R&Ds by the world’s scientific and technical community, resulted into acceptance and adoption of redefined SI units by CGPM at BIPM on November 16, 2018 by 60 member states [21]. Dr. D. K. Aswal, Director of CSIR-NPL, also voted for this landmark revision of the SI units. The new definition of SI units successfully replaced the artefact-based units and aptly opened up the new era for quantum world by linking all the seven base units, i.e. the kilogram (kg), metre (m), second (s), ampere (A), kelvin (K), mole (mol) and candela (cd) to constants of nature, which are invariants of time and space. Worldwide, the redefined SI units have been implemented on May 20, 2019, i.e. the ‘World Metrology Day (WMD-2019)’ in terms of physical constants. Since fundamental constants are inherently stable, these are chosen so that the redefined SI need not be modified again in near future to accommodate the possible improvements in the realization of base units [1, 21,22,23].

Further during WMD-2019, CSIR-NPL introduced redefined SI Units to the nation through a series of events and released 11 posters, policy document, recommendations and souvenirs. The posters released were based on BIPM theme poster (The International System of Units—Fundamentally Better); 2 NPL’s designed posters introducing redefined SI to nation in terms of constant of nature and highlighting impact of metrology on every moment of human life; released poster on Bhartiya Nirdeshak Dravya (BND®) and released 16 new CSIR-NPL certified BNDs; posters on special projects of socio-economic and industrial relevance being implemented at CSIR-NPL for creation of testing and calibrations facilities for LED lightings and testing of ballistic materials; posters on technologies transferred, commercialised, patents granted, number of users served through metrological services by CSIR-NPL during 2018–2019. In order to create awareness and promoting redefined SI units, CSIR-NPL designed and released special souvenirs, one key ring on SI units and another Metrology Wheels on SI Units, depicting the all the seven SI units and their links to corresponding fundamental constants. Further, for the commemoration of the event, CSIR-NPL also designed and painted a huge Wall of Metrology Graffiti in CSIR-NPL’s beautiful campus as a token of continuation of celebrations over the time. Director, CSIR-NPL declared open the Wall of Metrology Graffiti for the stakeholders.

As a national responsibility and keeping in view of the importance and recognition of new revision of SI, the CSIR-NPL prepared and released documents on (i) NPL Policy on Metrological Traceability [24], (ii) recommendations on the proposed changes to be incorporated in the National Council of Educational Research and Training (NCERT), New Delhi, textbooks and implement the new changes to impart cotemporary education to its students [25] and (iii) recommendations on the proposed changes to be incorporated in syllabi of metrology courses in graduate engineering and academic courses being taught in All India Council for Technical Education (AICTE), Indian Institutes of Technology (IITs), National Institutes of Technology (NITs), and other academic institutes [26].

On this special occasion, CSIR-NPL published and released a book titled as “Redefined SI Units and Glimpses of NPL Metrological Activities” to disseminate the information accommodating details on new changes, posters and documents mentioned above and the role of CSIR-NPL in strengthening the Indian metrological infrastructure for the Government representatives, certification bodies, regulators, policy makers, academic institutions, industries and public as a whole [27]. CSIR-NPL put efforts to highlight the new and advancement in metrological activities to masses.

3 Commemoration of 75th Foundation Day of CSIR-NPL

During the year 2019, CSIR-NPL started celebrating the CSIR-NPL Foundation Day by organising theme-based National Metrology Conclave (NMC) wherein the stakeholders are invited to share their experiences and issues for the possible solution by the NMI of India. As mentioned earlier, in order to commemorate the 75th foundation day of CSIR-NPL India, and as a mark of the Platinum Jubilee year, this year, i.e. January 04, 2021, was celebrated as special foundation day. On this occasion, CSIR-NPL organised a National Metrology Conclave 2021 (NMC-2021) under the theme ‘Metrology for the Inclusive Growth of the Nation’. During the NMC-2021, a series of events were organised and the key achievements of CSIR-NPL were dedicated to the nation. A galaxy of political and science leaders attended the events. These key accomplishments include releasing of a book, laying down of foundation stone of a national environment standard laboratory by Honourable Prime Minister and President CSIR through virtual platform and Honourable Union Minister, Science and Technology; Health and Family Welfare, and Earth Sciences and also Vice President, CSIR, Dr. Harsh Vardhan in the august presence of Dr. Shekhar C. Made, Director General, CSIR. The conclave included the technical talks delivered and messages from the eminent metrologists of leading NMIs of the world, namely Director, BIPM; Director, NMI South Africa and President, CIPM; President, PTB Germany and Vice President, CIPM; Director General, NMI Japan and Secretary, CIPM; CEO, NPL UK;CEO, NMI Australia, and the Director, NPL India.

One of the authors, as Director, CSIR-NPL delivered the welcome address. In his talk, he highlighted the chronology of events which lead to the foundation of CSIR-NPL and informed the august gathering about the overwhelming welcome received from the international community on the formation of CSIR-NPL, which was also published in Nature in 1947 and 1951 (Fig. 2) [15, 16]. He revisited the need of uniform measurement system worldwide through first metre convention, held in year 1875 to the formation of CGPM, CIPM and BIPM France. To harmonize the measurements in India efforts resulted in formation of NTH (National Test House) which was established way back in India in 1910 and then came BSIR (Board of Scientific and Industrial Research), which later become CSIR (Council of Scientific and Industrial Research), in 1942. He also cited Dr. Charles Volet, the then Director, BIPM, for his words to CIPM about the proposal of creation of NPL India, sent by the then Government of India to BIPM in 1953 for making NPL as NMI of India.

Fig. 2
figure 2

The creation of CSIR-NPL in 1947 and the coverage of the event published in Nature. Also depicted are the Gazette notifications of Legal Metrology Rules 2011 about keeper of the measurement standards and Ministry of Environment, Forest and Climate Change notifying CSIR-NPL as National verification agency for emission and ambient air monitoring instruments

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He further reiterated the main aim of the laboratory and providing measurement traceability, consultancy, technology transfer and know-how and training man power in metrology. Being one of the founding members in establishment of APMP, NPL India has fulfilled the expectations and hopes of its founding fathers and international communities since last seven decades and in the process registered 236 CMCs and 196 international inter-comparisons. He mentioned that NPLI very recently undergone its peer review on the quality system based on ISO/IEC 17025 : 2017 and ISO 17034 : 2016 through APMP to fulfil the requirements of CIPM MRA.

In his address, he further mentioned that CSIR-NPL has expanded its research areas, which are important to India and its industrialization to meet the challenges. Today CSIR-NPL provides the measurement traceability to more than 4000 customers in India as well as in SAARC nations. He also recalled that during the 26th CGPM in 2018, held in France, India along with 60 other member states played its role and voted for the landmark revision of SI units on the basis of fundamental constants, which was implemented worldwide from May 20, 2019, highlighting the importance of metrology as one of the key pillars in ensuring the quality of life interconnecting government, academia, industries and civil society together under various initiatives and programs. Therefore, metrology has its direct impact from trade, economy, and health to society as a whole.

The audiences were briefed about the current role and recent focus of CSIR-NPL on the accurate and precise time keeping using atomic clocks, environmental monitoring, biomedical devices, photovoltaic metrology, material metrology and certified reference materials (registered trade marked as Bhartiya Nirdeshak Dravyas, BNDs), realization of quantum standards for industry 4.0 in the spirit of AtmaNirbhar Bharat. The CSIR-NPL ensured the measurement traceability especially to PPE kits, medical devices and pharmaceutical industries during the pandemic time. He then briefed about the technical programme in the next session on role of metrology for inclusive growth of society, one of the goals of UN. He further thanked all the audience and dignitaries present and connected online.

3.1 Inaugurations/Releases by Honourable Minister of Science and Technology and Vice President, CSIR

3.1.1 Inauguration of Poster Gallery

To commemorate the occasion and highlight the foundation, glorious past, important milestones achieved in seven and half decades of continuous research and services and present activities of CSIR-NPL, one of the main galleries of CSIR-NPL was chosen to display all these glorious achievements in the form of self-explanatory, wall-sized posters to offer the general information about CSIR-NPL and its activities to all the dignitaries and visitors. The Poster gallery was inaugurated and thrown open to all the visitors to CSIR-NPL by the Honourable Union Minister of Science and Technology and Vice President, CSIR, Dr. Harsh Vardhan on this auspicious occasion as shown in Fig. 3. The gallery not only throws light on the CSIR-NPL metrological achievements but also casts the importance of metrology, unbroken chain of measurement traceability, the redefinition of SI base units in terms of natural constants, various derived units and their inter linkages to the base SI units, CSIR-NPL as NMI of India, various services of CSIR-NPL to the nation.

Fig. 3
figure 3

a Inauguration of the Poster Gallery by Honourable Minister of Science and Technology and Vice President, CSIR, Dr. Harsh Vardhan; Other dignitaries present were Dr. Shekhar C. Mande, DG, CSIR; Dr. D. K. Aswal, Director, CSIR-NPL and Dr. K. Lal, Former Director, CSIR-NPL b The dignitaries showing keen interest in poster to enlight the mandate of CSIR-NPL since its inception

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3.1.2 Screening of Short Animated Film on CSIR-NPL

A short animated film on CSIR-NPL foundation, progress and activities towards the nation’s development was screened on the occasion. The film depicted that in the year 1999, NPL, India signed the treaty on CIPM MRA and implemented its quality management system based on ISO/IEC 17025 to establish the international measurement equivalences for barrier free trade. Currently NPLI holds 236 CMCs and participated in 130 international inter-comparisons organised by BIPM and APMP to enhance its measurement capability and global visibility. These CMCs support more than 4000 test and calibration services annually to various industries of different sectors directly and more than 4 hundred thousand users in India and SAARC nations through secondary and regional laboratories. It also included that NPL India along with 60 member states also voted and witnessed the landmark decision on revision of SI base units based upon fundamental constants of nature on November 16, 2018, in CGPM general meeting at BIPM, France. After which as an NMI of India, CSIR-NPL implemented the revised definition of SI base units and releases the metrology policy and suggestions for revised definition in NCERT text books, syllabus in metrology courses in academia and legal metrology rules. To name a few mile stone achievements and unique duties, the film also depicted scientific endeavours of CSIR-NPL for the development of indelible ink used in electoral process, safe preservation and continuous maintenance and safeguarding the original copy of constitution of India. The vast role of CSIR-NPL was listed in terms of creation of key institutions of country, namely NABL, CEL, etc. The other scientific key achievements and services with which CSIR-NPL is playing its nation building role were also shown briefly such as National Atomic Timescale, generating and disseminating 2.8 ns accurate IST and its dissemination to ISRO towards AtmaNirbhar Bharat and safe digital India mission programs. The CSIR-NPL along with other reference material producers, is also producing cost effective certified reference materials (CRMs), trade marked as Bhartiya Nirdeshak Dravyas (BND®), for accurate and precise testing by 4 hundred thousand laboratories in India and supporting self-reliant India mission. The NPLI is also notified vide national gazette as national verification agency for certifying air-monitoring equipment in Indian ambient conditions under NPLI certification scheme (NPLICS).

3.1.3 Release of Book titled, “Metrology for Inclusive Growth of India”

To mark the historic occasion, a book published by Springer Nature [1] titled, ‘Metrology for Inclusive Growth of India’, describing the metrological activities, mandate and glorious past of NPL, was released by the Honourable Union Minister of Science and Technology and Vice President, CSIR, Dr. Harsh Vardhan (Fig. 4). The book edited by Dr. D. K. Aswal and contributed by most of the CSIR-NPL Scientists, elucidates the implication of metrology in details for the wide ranging growth of India and its applications in physico-mechanical metrology, electrical and electronics metrology, measurements and dissemination of Indian standard time, Bhartiya Nirdeshak Dravyas (BND®) and various other parameters related to microwave metrology, environment, biomedical, materials. It also introduces the ‘Aswal Model’, which connects metrology, unison with accreditation and standards, science and technology, government and regulatory frameworks, civil society, media and industries. The book exclusively enlists and presents critical analyses of contributions made by CSIR-NPL through its scientific contributions and apex measurement facilities of international equivalence in the areas of industrial growth, strategic sector growth, environmental protection, cyber security, sustainable energy, affordable health, international trade, policy-making, etc. The book is very useful and expected to serve the purpose of a reference guide for science and engineering students, researchers, metrologists, policymakers and entrepreneurs. The book was appropriately appreciated by the Honourable Prime Minister through a citation letter.

Fig. 4
figure 4

Release of Book titled, “Metrology for Inclusive Growth of India” (Left to Right: Dr. D. K. Aswal, Dr. Harsh Vardhan and Dr. Shekhar C. Mande)

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3.1.4 Release of Thesaurus for Metrology (M-Map)

On the occasion, the Honourable Union Minister also dedicated the online ‘Thesaurus of Metrology’, developed by CSIR-NPL with the support of different subject experts of CSIR-NPL. The thesaurus would be helpful for students in building their comprehensive of introducing with core concepts of the subject in semantic manner, while for subject experts it would serve as an aid and provide additional vocabulary for literature search and quality academics. For the semantic representation of metrology concepts, CSIR-NPL has also developed an online platform ‘m-Map’ for the structured trade work of domain concepts. The ‘m-Map’ platform created for Thesaurus of Metrology would be helpful for understanding of metrology for all the people.

3.1.5 Excerpts from the Speech of Honourable Minister

In his address, honourable Dr. Harsh Vardhan congratulated the NPL as well as CSIR on the occasion and said, ‘The expertise found within the many science laboratories of India is driving the ground-breaking research and development and is a key force in helping our country become a leading science superpower’. He further stated that the ‘scientific community has been the most prominent in the last one year. The Herculean efforts made by our scientists have finally paid off.’ The Minister said, ‘Today, we have several vaccines that have been developed across the world, two of which have been developed at a record-breaking speed and granted authorization in India’. He pointed out, ‘It has all been possible due to the exemplary and collaborative efforts of scientists across the world, it has been an extraordinary level of sharing of science and its knowledge’.

The Minister expressed his belief, “Our scientists can give us game-changing ideas and the opportunities that can be harnessed to boost our industry, create new jobs, and make a real difference in everyday life. Science can be the biggest equalizer. It can ensure that the poorest man leads a comfortable life with just simple ideas and innovations. That’s what I want you all to do”.

He further said that CSIR-NPL which is the NMI of India; Member of the CGPM, BIPM, an International Intergovernmental organisation constituted by diplomatic treaty, i.e. ‘The Metre Convention’; and Founder Member of the Global Regional Metrology Organisation, i.e. APMP, has the mandate to realize, establish, upgrade, maintain and disseminate the measurement standards by Act of Parliament. On the occasion of CSIR-NPL entering its platinum jubilee celebrations, a series of events have been organised with world science leaders. More than 50 thousand participants have joined through online including several metrologists, industrialists, regulators, policy makers, academicians and students. Several other dignitaries from all over the world have also participated in the event to commemorate the 75th Foundation day of this premier laboratory. A technical session on the theme ‘Metrology for Inclusive Growth of India’, is chaired by Prof A. K. Grover, Chairman, Research Council, CSIR-NPL. Talks and technical deliberations by Directors of BIPM and Directors/Science Leaders of various other NMIs (Germany, UK, Japan, South Africa, Australia and India) are some of the other highlights of the Conclave.

3.2 Unveiling/Dedication/Laying Foundation of the Following by Honourable Prime Minister and President CSIR

One of the highlights of the events was the online presence of Honourable Prime Minister, Government of India and President, CSIR, New Delhi, Mr. Narendra Modi and sparing his valuable time to unveil/Dedicate/Lay down Foundation Stone of several scientific facilities for national Importance and global relevance, which are described later on in this section. Director General, CSIR, Dr. Shekhar C. Mande greeted and welcomed the honourable Prime Minister and President, CSIR, Mr. Narendra Modi for his gracious online presence, Union Minister present on the dais and also other online dignitaries of sixty nations worldwide. He also extended his heartily felicitations on behalf of the CSIR family to all the NPL members for entering into the glorious 75th year.

3.2.1 Unveiling of ´75th Commemorative Plaque' Depicting the IST and BND Network

For the historic celebrations of 75th Foundation Day, CSIR-NPL has innovatively conceptualized the ‘75th Commemorative Plaque’ depicting the IST and BND Network across the country to percolate the spirit of AtmaNirbhar Bharat in every sector. The plaque indicates the locations of users of National Atomic Clock generating IST™ and its Pan-India dissemination. The plaque also shows the locations of Bharatiya Nirdeshak Dravya (BND®) and links with reference material producers across the India. The Honourable Prime Minister unveiled the ‘75th Commemorative Plaque' to the nation as shown in Fig. 5 (Top left).

Fig. 5
figure 5

Honourable Prime Minister Shri Narendra Modi dedicated, top left: 75th Commemorative Plaque; Top right: National Atomic Timescale; Bottom left: Bharatiya Nirdeshak Dravya (BND®); and Bottom right: laid down the foundation stone of the National Environmental Standard Laboratory

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3.2.2 Dedication of 'National Atomic Timescale'

CSIR-NPL is the timekeeper of the nation using atomic clocks. On this auspicious occasion, Honourable Prime Minister, Mr. Narendra Modi, dedicated the National Atomic Timescale to the nation as shown in Fig. 5 (Top right). CSIR-NPL realizes and maintains the Indian Standard Time (IST™) traceable to Coordinated Universal Time (UTC) with an uncertainty of ± 2.8 ns. A bank of ultra-stable atomic clocks are used to realize the National Primary Timescale, IST™, and its dissemination across the Indian subcontinent is done through the network time service and satellite links. CSIR-NPL is on the mission of “One Nation One Time” to synchronize all the clocks in the country to IST™ for digital transformation and cyber security. The IST™ traceability to ISRO’s timing centres located at Bengaluru and Lucknow is already established for their space programme. The CSIR-NPL is establishing five traceable secondary timing centres at RRSLs across India at five centres, namely Faridabad, Bengaluru, Bhubaneshwar, Ahmedabad and Guwahati for Department of Legal Metrology, as regional timing centres for providing IST dissemination services to the various sectors and stakeholders in realizing the mission of safe digital India. Sectors like telecommunication, cyber security, cyber-physical systems, ISRO for the crucial NavIC program, air traffic control, secure banking and stock transactions, geodesy, deep space navigation, radio telescopespower grids, etc., increasingly require precise time synchronization. An estimate shows that an economic impact of IST synchronization in these sectors is more than 10% of GDP.

Various technologies, such as time dissemination through telephones, NTP, PTP, CV/AVGNSS & TWSTFT, are available for the time and the frequency synchronization. Along with time realization and dissemination services, CSIR-NPL also pursues R&D on primary standards. India’s first Caesium fountain (NPLI-CsF1), approved by BIPM as a primary frequency standard, was indigenously designed and developed at CSIR-NPL. The focussed and concentrated efforts are being placed on the design and development of a single trapped Ytterbium ion-based optical frequency standard, which would possibly be used for redefinition of SI second. CSIR-NPL will become ready for adopting and implementing the redefinition of SI second, which is expected in 2026. At present, IST is disseminated across the country through calibration, network time services, and satellite links [28,29,30].

3.2.3 Dedication of 'Bhartiya Nirdeshak Dravya (BND®)' for self-reliance

Honourable Prime Minister. Mr. Narendra Modi also dedicated the “Bharatiya Nirdeshak Dravya (BND®)” for the nation for self-reliance and to support the testing and calibration laboratories across the country for quality assurance at par with International Standards as shown in Fig. 5 (bottom left). Reliability of the laboratory results depends upon the traceable calibration through certified reference materials (CRMs). These CRMs are used to calibrate the testing equipment with utmost accuracy. These CRMs traceable to SI units are produced under the stringent conditions following the international standards for quality assurance and the data as per international acceptance. These CRMs are also used for calibration, testing, quality control, method validation purpose, assigning the values to other tested materials and finally to maintain or establish traceability to conventional scales. The Indian CRMs are registered as Trademark name Bhartiya Nirdeshak Dravaya (BND®). These BNDs are used by industries, government sectors and academia to ensure the best accuracies with minimum uncertainties in measurement through calibration of instruments, validity of measurements and method validation for quality assurance. As on today, India imports CRMs worth several hundreds of crores. Being the NMI, it is the responsibility of CSIR-NPL to overcome this flow of foreign exchange and produce as many CRMs and become self-reliant. In order to cater the demands of Indian Industries and huge potential of CRMs production, CSIR-NPL has started a massive mission mode programme in association with Ministry of Commerce and Industry (MoC) for indigenous production of CRMs/BNDs. Many MoUs have been signed with several Reference Material Producers (RMPs). Such coordinated and sustained initiatives taken by CSIR-NPL would surely entail a significant change in the socio-economic structure of the nation through an effective and reliable quality control and assurance programme. This would help enhancing barrier-free export and import of goods, services and CRMs as well as saving foreign exchange. Production of BNDs would also help in employment generation; enhance global trade and international visibility of India [31, 32].

3.2.4 Laying of the Foundation Stone of 'National Environmental Standard Laboratory'

On this historic occasion, Honourable Prime Minister Shri Narendra Modi virtually laid down the foundation stone of the National Environmental Standard Laboratory, as shown in Fig. 5 (bottom right) for the self-reliance in certification of ambient air and industrial emission monitoring equipment through CSIR-NPL Indian Certificate Scheme. The quality of data in air pollution monitoring instruments is vital in concluding the correct and reliable results. Role of measuring instruments and their calibrations are the major issues that also need to be addressed. At present, most of the used instruments are imported having product certifications from international agencies, namely United States Environmental Protection Agency (US EPA), Technicher Überwachungsverein (TUV), Germany, Monitoring Certification Scheme for Equipment, personnel and organizations (MCERTS), UK, etc. The calibration certificates issued with such instruments are as per the environmental conditions of the certification/manufacturing nation. However, the prevalent environmental conditions in India are normally different. This affects the quality and reliability of measurements taken with these equipments operating for a long time in the Indian conditions and warrants a revisit of the certification process at regular intervals.

The value of global market for the air pollution monitoring system is estimated to be about US$ 3997.8 million, and by the year 2025 it is expected to reach US$ 7118.7 million. Majority of such equipments along with their compliance with the concerned regulatory requirements will be installed worldwide. India along with other third world countries are the major target economies, which will offer a great market opportunity. CSIR-NPL is designated, by the ministry of Environment, Forest and Climate Change (MoEF & CC), as verification and certification agency for emission and ambient air pollution monitoring equipments in India through the notification in the Gazette of India (shown in Fig. 3). Therefore, “CSIR-NPL India Certificate Scheme (NPLI CS)” is developed by CSIR-NPL to provide certification of performance evaluation for air pollution monitoring equipments. With financial support from MoEF & CC, the CSIR-NPL is establishing a state-of-the-art ‘National Environmental Standard Laboratory’ for the performance checking of ambient air and emission pollution monitoring instruments and devices. These instruments include Continuous Ambient Air Quality Monitoring System (CAAQMS), Online Continuous Emission Monitoring Equipment (OCEMS), etc. This will provide the required testing and calibration facility for air pollution monitoring equipments. This initiative will also support the goals of ‘AtmaNirbhar Bharat’ set by the Honourable Prime Minister of India in the area of air pollution monitoring [19, 33]. All imported as well as indigenously developed environmental monitoring equipment’s will be certified using this facility. NPLI CS will be equivalent to those of the international certification schemes like MCERTS, US EPA, TUV, etc., and save over several thousands of crore Rupees worth of foreign exchange that are annually spent on calibration and certification of such equipment from abroad. NPLI CS will facilitate indigenous development and manufacturing of Air Quality and Industrial Emission monitoring equipment, making India self-reliance as well as capable of exporting.

3.2.5 Address by Honourable Prime Minister and President, CSIR, Mr. Narendra Modi

The honourable Prime Minister thereafter addressed the whole scientific fraternity attending the National Metrology Conclave from all over the globe through online platforms as well as physically in some of the institutions. Figure 6 depicts a small glimpse of more than two hundred thousand participants hearing one of the most inspiring speeches delivered by political or science leaders. The entire address, as published in Press Information Bureau (PIB) of India, is reproduced and included in Table 1 in Hindi as well as in English versions [34,35,36,37].

Fig. 6
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Address by Honourable Prime Minister and President, CSIR, Mr. Narendra Modi

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Table 1 The Hindi and English versions of Honourable Prime Minister’s address delivered during National Metrology Conclave held on January 04, 2021 at CSIR-NPL, New Delhi to commemorate the Platinum Jubilee Foundation Day of the Laboratory [34,35,36,37]
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4 Technical Session of National Metrology Conclave [37]

The second half day of the National Metrology Conclave was exclusively devoted on the technical talks, discussions and deliberations on the theme Metrology for Inclusive Growth of India. Prof. Kehar Singh, Ex-Member, NPL Research Council and Chairman of the Session, welcomed all the speakers, the NMIs Directors and Executives, other online participants across the globe and the audience physically present in the technical session. He cited the evolution of metrology from primitive metrology mainly focused about human activities and trade or commerce in India, China, Egypt and Mesopotamia, the ancient civilizations, to its present form in modern era, viz. micro- and nanometrology. He emphasized on the plethora of books, review articles and popular journal (Metrologia) featuring metrology which is useful practically to all spheres of human importance, namely semiconductor industry, forensic, material science, clinical practices, automotive industries, environment, chemical industries. He, at the juncture, also highlighted the dire need of M. Tech level courses to be conducted on the metrology subject in India.

4.1 Comparable Measurements for a Digital World

The first talk was delivered by none other than the Director, BIPM, Dr. Martin Milton, on a most contemporary and relevant topic, i.e. Comparable Measurements for a Digital World. First of all, he congratulated the Director NPLI and its scientists highlighting the historic letter wherein the then BIPM Director briefed the CIPM about NPL India and the Metre Convention in October 1953, just after the establishment of the NPL in 1950 and finally India acceded to the metre convention on January 11, 1957. Having mentioned that six outstanding Indian scientists (all Directors of the NPL) were members of CIPM. He also briefed about the Task group formation on the digital SI framework towards CIPM’s latest initiative (via New Digital Transformation Project) to provide a Digital SI framework for the documents and data that are fair and trustworthy. He further added about the CIPM efforts for NMIs to do Metrology in the fighting against Covid-19, and BIPM and OIML have decided that the theme for World Metrology Day-2021 would be Measurement  for Health.

4.2 Metrology for Renewable Energies: Challenges for the Twenty-First Century

Prof. Joachim Ullrich, President, Physikalisch-Technische Bundesanstalt (PTB), Germany and Vice President, CIPM, explained the role of German NMI, i.e. PTB, towards renewable energies and underlying challenges. In context of India, he highlighted that how PTB is committed in renewable energy projects worldwide, especially developing QI and Primary Reference Solar Cell Measurement System, Climate Protection & Biodiversity and in Green Economy (Water Monitoring of the Ganga River). India centric long history of partnership, especially, SAARC project to strengthen regional cooperation in metrology, were also highlighted. As the talk progressed, Dr. Ullrich discussed sources for climate change, their challenges and mitigation schemes in detail categorizing as renewable energy harvesting, handling and storage of harvested renewable energy and efficient use of energy, placing metrology playing its central role everywhere. His talk ended with congratulating NPL on the anniversary of its foundation. He further informed that as a token of appreciation of long association PTB and CSIR-NPL, the PTB will present CSIR-NPL a silicon sphere. Since a personal handover is not possible at the moment, the gift was presented symbolically as a photograph for the time being. The real silicon sphere is on its way to India [38].

4.3 Impact from Metrology

Dr. Peter Thompson, CEO, NPL, UK, talked about the importance of metrology by quoting famous quotation of Lord Kelvin, that “To measure is to know. If you cannot measure it, you cannot improve it”. In the era of current pandemic situation, he highlighted the work of NPL UK citing its new services for pandemic Covid-19 management in response, measurement for economic recovery, technology and measurement foresighting. He emphasised on the importance of sustainability in the context of Climate, Energy and Environment. His talk ended with the remarks that NPL, UK, is looking forward to the future of metrology dealing in digital SI, complex systems and more importantly the confidence in data.

4.4 Metrology for Building a Sustainable Society

The next talk was delivered by Dr. Takashi Usuda, Director General NMIJ, Japan, and Secretary, CIPM, on the recent activity carried out at NMIJ in metrology for building a sustainable society. He briefed about the organizational structure of National Institute of Advanced Industrial Science and Technology (AIST), the largest scientific institute of Japan which coordinate to enable sustainable society. His talk progressed with the highlights of current inspection technologies and cost conscious technologies of research laboratories for sustainable infrastructure, large but crucial involvement of IT and automation for inspection visualization of strain, defect and displacement measurement by imaging. He also underlined the importance of collaborations by highlighting some of NPL India and NMIJ collaborations in past, starting from 1998 along with members from NMIJ in the editorial board of MAPAN. He ended his talk with looking forward to NPL’s participation in International Measurement Confederation (IMEKO) in 2021 and APMP-2022 to be organized by Japan at Yokohama and Tokyo.

4.5 The Contribution of Metrology to the Intra-Trade and Growth in Africa

Dr. Wynand Louw, Director of Research and Technology Development, NMISA, South Africa; Head of AFRIMETS Secretariat and President, CIPM talked on behalf of Mr. Mukahufhi, CEO, NMISA, South Africa. Highlighting the importance of metrology to the intra-trade and growth of Africa, he outlined the 10 flagship projects in 7 inclusive agendas of African union by year 2063, which mainly include a high standard of living, quality of life, well educated citizens and skills revolution underpinned by Science, Technology and innovation, healthy and well-nourished citizens, transformed economies and job creation, modern agriculture for increased production & productivity, blue ocean economy for the accelerated economic growth, environmentally sustainable and climate resilient economies and communities. Further, he talked about the challenges and the opportunities to strengthen the role of measurement science within the society, while actively developing new measurements that are fit-for-purpose for uniquely African problems to enable product safety, quality and compliance. Mentioning the African challenge of feeding approximately 2  million  people by 2050, he highlighted the role of QI for the AfCFTA in meeting them and pan African QI. He also briefed that expected growth of the intra-AfCFTA exports to AfCFTA partners would rise in many aspects which he sees resulting a rising growth in exports by 46% from Africa to the rest of the world. The talk also outlined the African fight against Covid-19 with printing of 3D medical masks and plans towards development of CRMs.

4.6 Metrology for Sustainable and Inclusive Development

Dr. B. Warrington, CEO, NMIA, Australia, warmly congratulated CSIR-NPL on its Platinum Jubilee celebrations. He quoted that enhancing science, technology and research collaborations is an important pillar and informed that a Joint Statement on a Comprehensive Strategic Partnership was held recently between the Australian and Indian Governments during June 2020. He further pointed the underlying importance of metrology for attaining 17 essential goals for sustainable and inclusive development of a nation, which were adopted by UN member states at the UN Sustainable Development Summit, held in 2015 at New York. The underlying metrology requires to meet the challenges in the development of technical capabilities of measurements in various key disciplines primarily including, chemical, physical, biological, legal measurements along with their shared capabilities but also affects major sectors, namely health, energy, environment and food. The five APMP focus groups, important for international metrology framework and directly related to sustainable and inclusive growth, therefore justify their relevance and need attention. He further quoted Director of UNIDO’s Department of Trade, Investment and Innovation, “Metrology is essential to protect the planet, ensure dignified lives for all people, and achieve inclusive economic growth and prosperity”, said at the 26th CGPM in Versailles in 2018. He further explained few goals and current challenges involved therein including legal metrology, energy, preparation of reference material, proficiency testing and healthcare during Covid-19 crisis keeping NMIA in centre citing examples of different case studies. He finally mentioned future areas of metrology as transport, advanced manufacturing, defence and aerospace, digital and cyber and global partnership and cooperation for sustainable development.

4.7 Metrology for Inclusive Growth of India

After these luminary talks and messages from eminent metrologists, Dr. D. K. Aswal, Director, CSIR-NPL, presented his views with quotation, “the economic growth that is distributed fairly across societies and creates opportunity for all”, of the Organization for Economic Co-operation and Development (OECD). He mentioned that one of the main challenges of India is serving  it's  huge population. He explained the existing models of growth and their bottlenecks/shortcomings together with the newly developed Aswal model, which is based upon metrology-driven quality infrastructure (QI) [1]. In this model, metrology-driven QI synergizes Government, industry, academia and society in much better way following the same measurement standard and as a result, the knowledge can be transferred into the wealth, leading to the high-quality life of citizens as well as high economy. While discussing the models, he further added his experience on effect of having non-uniform standards followed by different sectors of economy, namely Government, Academia, R&D, Industries, Society, Environment, etc. He further pointed out the inevitability of uniformity of standards, traceable to SI units and use of BNDs, i.e. the need of a strong QI in the country to be followed by each sector. He explained the Aswal model giving glimpses of the analysis of different domains including a few such as, technology development and industrialization, cyber-physical systems and cyber-security, affordable healthcare, clean environment to level playing field in society for inclusive growth of the country.

4.8 APMP Award for Developing Economies and Citation Presentation

APMP Award for Developing Economies for the year 2020 was presented to Dr. Sanjay Yadav, Senior Principal Scientist by the Director, CSIR-NPL, and Prof. Kehar Singh on the historic occasion for his outstanding contributions in his career in metrology. To name a few, he contributed significantly in registering several Calibration and Measurement Capabilities (CMCs) in KCDB, successful participation and contribution in various international key comparisons for compatibility, equivalence and global visibility of the standards, development of several primary and secondary pressure standards, publication of many research papers in SCI journals, various copyrights, patents, technologies and know-how’s. The award was conferred to him by APMP Secretariat, Japan, in the recently held APMP General Assembly and Related Meetings online during November, 2020 [34]. He is the recipient of several awards and scholarships in his meritorious career from number of reputed agencies and organizations including JICA Fellowship of JAPAN (1998) and Commendation Certificates from SASO, Saudi Arabia (2003). Apart from his present key role as Editor-in-Chief of MAPAN-The Journal of Metrology Society of India (MSI) since year 2016, he is also heading the Physico-Mechanical Metrology Division of CSIR-NPL, which is responsible for realization and maintenance of four important SI base units, namely kg (kilogram), m (metre), K (kelvin) and cd (candela) along with other derived units, viz. Pa (pressure, vacuum), Hz (ultrasonics), N (force), N/mm2 (hardness), W/m2 (acoustics), Hz (vibration) and m3/s (fluid flow).

4.9 Commemorative Messages Received from Leaders of BIPM and Various NMIs on the 75th Foundation Day

A number of messages received from the world metrology leaders from BIPM and various NMIs on this auspicious occasion of NPL Foundation Day are summarized in Table 2.

Table 2 Messages of Leaders of BIPM and various NMI
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4.10 Closing Remarks for NMC

The important historic event was also graced online by Prof. A. K. Grover, Chairman, Research Council, CSIR-NPL. Interestingly, in his closing remarks, Prof. Grover drawn an amusing analogy between events organised during 1950 and 2021 by quoting the fact that the NPL building was also inaugurated remotely on May 20, 1950, by the Deputy Prime Minister of India, Sardar Vallabh Bhai Patel, like the occasion is being celebrated today, i.e. on January 04, 2021, and many dignitaries are connected to NPL via online mode. He also highlighted the challenges before India in present context for its inclusive growth and among the other issues; the population is a major one. The concluding remarks was finally made by Prof. Kehar Singh. In his brief concluding remarks, he outlined the messages from Honourable Prime Minister, Minister and Director General, CSIR, the usefulness of technical session and, scientific excerpts from the luminaries, who graced the occasion from other leading NMIs. He mentioned the book, released on the occasion, titled, ‘Metrology for Inclusive Growth of India’, edited by D. K. Aswal about the importance of metrology. He also suggested the need of compendium of literature to mark the work done by CSIR-NPL Scientists on regular interval of time. He appreciated the conduct and very well management of the programme throughout and wished all the best for future endeavours in metrology on the occasion of entering the 75th Platinum jubilee. As a follow-up, the present feature article is prepared as a compendium of information for the future references.

5 Collaborative Programmes

The CSIR-NPL has been always endeavouring to have collaborative programmes with various NMIs and other esteemed institutions to acquire metrological expertise and gain knowledge to enhance the skills of its scientists. Such national and international programmes are utilized to impart and train the experts and technical staff from various countries at CSIR-NPL. Though the list of such co-operations is big, few of the noticeable and running programmes are summarised in this section.

5.1 International Collaborations

Time to time, CSIR-NPL has been implementing several international cooperation programmes to achieve the mandate of the laboratory. One of the significant technical cooperation signed in 1971 was with PTB, Germany, to enhance its standards facilities. Several new standards facilities were established under this programme apart from the upgradation of the existing standards and calibrations facilities. In Phase-1, this programme was continued till 1984. In continuation of this programme (Phase-2), during 1989–1998, few new facilities of standards and calibration services were established at CSIR-NPL along with upgradation of Central Workshop.

During 1981–1987, CSIR-NPL worked on a project sponsored by United Nations Development Programme (UNDP) and many of the primary standards of vacuum and pressure were established which are still in service even today with international compatibility. In another Indo-US collaborative project, transfer leak standards were established during 1993–1996. Various advanced surface analytical facilities (XPS, AES, SAM, etc.) were also established under Indo-US project during the period 1994–1996 [39,40,41].

The SAARC-PTB project has been running since 2006 for strengthening, sustainability and improvement in access to trade and demand oriented quality infrastructure in South Asia region through metrology by sharing of knowledge, experience, expertise and information among the South Asian Association of Regional Cooperation (SAARC) Member States. The project is carried out in close collaboration with the network of NMIs and National Accreditation Bodies within SAARC region. On regional level, the project’s main cooperation partner is the South Asian Regional Standards Organisation (SARSO), a specialized body of SAARC. This project is funded by the PTB, Germany. The CSIR-NPL has been providing all the technical support to SAARC NMIs by providing calibration and testing services, training (including on-site), inter-comparisons, etc. in various technical parameters. This project was started in 2006 and two of its phases have successfully been completed. Currently in Phase-3 (2018–2021, extended upto 2022 due to Covid-19 pandemic), one preparatory workshop (Fig. 7) and three Scientific Interaction Programmes (SIPs) have been completed in various parameters and two inter-comparisons on length and volume are under process to establish the degree of equivalence among NMIs in SAARC region. These comparisons will provide evidence to support the calibration and measurement capabilities (CMCs) of SAARC NMIs [42].

Fig. 7
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A preparatory workshop on inter-laboratory comparison and scientific interaction program was conducted under PTB-SAARC project during November 19-December 05, 2019

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Scientists of CSIR-NPL had visited for longer durations (6 months/12  months) in National Measurement and Calibration Laboratory (NMCL), the NMI of Saudi Arabia, and also as Saudi Arabian Standards Organization (SASO) to establish their standards, quality documents, etc. in various technical parameters under CSIR—SASO Bilateral Technical Cooperation Programme. Some of the CSIR-NPL experts also extended support to SASO in the development and implementation of Quality System and accreditation mechanism. Technical Officers of NMCL and SASO have also visited different standard laboratories in CSIR-NPL time to time to acquire training and/or enhance their metrological expertise and knowledge.

5.2 National Collaborations

The CSIR-NPL provides traceability to Regional Reference Standard Laboratories (RRSLs), Department of Legal Metrology under Ministry of Consumer Affairs, Food & Public Distribution. The RRSLs send their reference standard weights every three years and metre bar every five years to CSIR-NPL for calibration. As per the Legal Metrology (National Standards) Rules, 2011, only CSIR-NPL can provide traceability to RRSLs to maintain weights and measures system of the country [17].

The CSIR-NPL also works in close association with BIS, the National Standard Body, in formulating the documented Indian Standards (IS) for harmonisation and improvement of quality of goods. In India, some of the standards are developed indigenously, while some of them are adopted as it is or modified from the ISO and/or IEC standards based on Indian conditions. CSIR-NPL shares technical knowledge, expertise and advices to the BIS in formulating IS standards (IS) in its technical committees as members, experts, Chairman, etc. [43].

As discussed in Sect. 2.1, NABL (Accreditation Body in India) was borne and nurtured in CSIR-NPL. Even after established as an independent entity, NABL has long association with CSIR-NPL and both have been working together for establishment and upgradation of quality infrastructure of the country. The CSIR-NPL provides traceability to the accredited laboratories to maintain quality system based on ISO/IEC 17025. Numbers of Scientists and Technical Officers have been supporting NABL in accreditation process as Lead Assessors and Technical Assessors. Some of the senior Scientists and Technical Officers are also chairs and members of the various core accreditation committees as well as acting as Chairman of NABL. CSIR-NPL supported NABL by organizing proficiency testing (PT) programmes in various parameters to monitor the performance of the accredited laboratories [11].

6 Dissemination of Metrology—Services, Skill Trainings and Technical Supports

6.1 Apex Level Calibration and Testing Services

Over the years, CSIR-NPL has developed apex level measurement and calibration capabilities for all the SI base units, i.e. the kilogram, kg (mass); the metre, m (length); the kelvin, K (temperature); the candela, cd (luminous intensity); the second, s (time); the ampere, A (electric current) and the mole, mol (amount of substance). Further, measurement capabilities have been developed for their derived parameters used to quantify various other important quantities, namely density, viscosity, area, volume, roundness, flatness, roughness, humidity and moisture, luminance, illuminance, luminous flux, colour temperature, colour coordinates, spectral irradiances, irradiance, pressure, vacuum, ultrasonic attenuation, ultrasonic velocity, ultrasonic power, vibration amplitude, sound pressure, sound absorption and transmission coefficient, mass and volume flowrates in fluids flow, force, torque, hardness, voltage, current, electrical power, energy, impedance, resistance, capacitance, inductance, magnetic field and flux etc. To face the new challenges of advanced technologies and demand from the stakeholders, the new measurement standards and facilities are developed/being developed time to time including those of the new as well as existing parameters. Keeping in view of such sustained demands, the new time synchronisation facilities, environmental, BNDs and biomedical measurement standards are being developed [44]. These measurement standards and measurement facilities have been playing their profound role providing traceability and expertise to stakeholders and as a result in the growth of Indian economy, together with the mission programmes of Indian Government, namely Make in India, AtmaNirbhar Bharat (self-reliant India) and other initiatives. The traceability service of CSIR-NPL through apex level calibration for various parameters has been the foundation for reproducible and trustworthy products from these Indian industries and stakeholders. Further apart from this CSIR-NPL is not only playing its important role in providing technical and consultancy services to industries and entrepreneurs, but also playing a silent role by providing technical experts for many national and international committees in the areas of metrology, standardization, accreditation or policy formulation, which form the basis of over-all inclusive growth of the country.

6.2 Specialised Training Programmes and HRD Activities

The CSIR-NPL regularly organises training and academic services to train participants from different industries, Government departments, NABL accredited laboratories, legal metrology offices or other users and stakeholders to provide them technical expertise with hands-on experience related to testing and calibration of various measuring equipment for different parameters. Many of such training programmes have been organized and being organized for candidates participating from India and abroad, namely from Saudi Arabia and  SAARC countries like Sri Lanka, Bangladesh, Nepal, Bhutan, Afghanistan (for example Fig. 7), etc. [45, 46].

The CSIR-NPL is also offering academic programme Doctor of Philosophy (Ph. D.) for post-graduate students. Discharging its duty as an NMI of India and apex metrology laboratory, CSIR-NPL also runs skill development programmes offering one-year Post Graduate Diploma (PGD) programme under Precision Measurement and Quality Control (PMQC) every year to train and guide young engineering graduate/diploma students by providing theoretical lectures as well as experimental demonstrations to upgrade and enhance their technical skills and understanding, related to precision measurement. Both the programmes are affiliated to Academy-CSIR (AcSIR), established in 2010 (by an Act of Parliament vide The Gazette of India as an Institution of National Importance). The PGD certificate course enables them to serve better in metrology and quality management-related industries.

6.3 Metrology Society of India, Organisation of Advances in Metrology (AdMet) Series of National and International Conferences and Publication of MĀPAN Journal

Metrology Society of India (MSI) was formed and registered in CSIR-NPL on January 01, 1984, under the Society Act XXI of 1860 by a group of senior scientists of CSIR-NPL and some other stakeholders to promote and disseminate metrological activities in the country. The MSI in association with CSIR-NPL annually organizes Advances in Metrology (AdMet) series of national and international conferences to highlight the importance of metrology in every discipline and to provide a forum to leading metrologists worldwide, researchers, students, academicians, and industries to share, exchange, interact, discuss, exhibits and publish the advancements and latest development in the field of metrology. Until now, the MSI has organised 10 international and 7 national conferences in AdMet series apart from several other events. The MSI has also created its four chapters in North, South, East and West regions in India. Over the time, people from various sectors including graduate students have joined the society as members. At present, total members are more than 2000 including corporate members [47].

The MSI in association with CSIR-NPL and CSIR also publishes a leading SCI indexed journal of metrology, i.e. MĀPAN-Journal of Metrology Society of India (JMSI). It is a quarterly publication, publishing latest development and researches in the area of measurement science. The broad coverage area of publication is exclusive devoted on scientific, industrial and legal metrology. The articles published are in the form of original work, tutorial or survey papers in any metrology related area; reviews and analytical studies in metrology; case studies on reliability, uncertainty in measurements; and reports and results of inter-comparison and proficiency testing, which are original and innovative [48]. Apart from metrologists within India, the editorial board of the journal includes the spectrum of eminent metrologists from leading world NMIs [49].

7 Directors of CSIR-NPL

On this occasion, the authors considered it is most appropriate to include all the eminent science leaders who served as Directors of this premier institution. All these Directors of the CSIR-NPL have significantly contributed in the glorious and illustrated journey of 74 years with their tenures. The journey of CSIR-NPL as NMI was started signing Metre Convention by Dr. K. S. Krishnan in 1957 and still continued with adoption of resolution of redefinition of SI units in November, 2018 and implementation of redefined SI units in 2019 on World Metrology Day, i.e. May 20, 2019, by Dr. D. K. Aswal, the present Director. Figure 8 shows the tenures of all the Directors who have played a leading role to move forward this premium national laboratory serving the nation as NMI.

Fig. 8
figure 8

Directors of CSIR-NPL with their tenures

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8 Some of the Milestones Achieved by CSIR-NPL

Over the years, CSIR-NPL has done exceedingly well and achieved several noticeable milestones of national and international eminence. It is difficult to describe all such accomplishments is a single article due to obvious reasons of limitation of space. However, some of the major achievements are described as follows;

8.1 Development of Indelible Ink—the Mark of Democracy

The indelible ink, the mark of Indian democracy, used during the elections, was developed by CSIR-NPL in the year 1952. The ink contains silver nitrate. When it is applied on the nails, it reacts and with further exposure to light, the dark purple colour mark appears. Once ink is applied on the fingernails its mark remains on the fingernail for about two days to a month depending upon the body temperature of person and the environmental conditions. This technology was transferred to M/s Mysore Varnish and Paints Ltd. (MVPL) in the year 1962 for mass production [50]. Currently, MVPL is exporting the indelible ink to about 25 countries, such as, Thailand, South Africa, Nigeria, Ghana, Singapore, Malaysia, etc. Therefore, this indelible ink developed by CSIR-NPL is a gift to India and several other countries.

8.2 Contributions in Antarctica expeditions

CSIR-NPL played national leadership in the four Indian Scientific Expeditions to Antarctica (ISEA). The 8th and 31st Indian Scientific Expeditions were noticeable as important milestones for Indian Antarctic mission when the two permanent scientific bases, i.e. Bharati (69° 24' S, 76° 11′) and Maitri (70° 46' S, 11° 43' E), were established by India. With the establishment of these two permanent stations, India joined the elite club of nations having more than one scientific base in Antarctica. During 28th ISEA (2008–2009) CSIR-NPL had played a pivotal role in establishing an advanced Polar Space Physics Laboratory (IPSPL) at Indian Permanent Research Base ‘Maitri’, Antarctica (Fig. 9) on the occasion of International Polar Year (IPY). The permanent research base station ‘Maitri’ plays its crucial role in continuous and real-time monitoring of ionosphere to address the scientific interest of high latitudinal ionospheric consequences, caused by the modulation of near-earth space environmental conditions [51].

Fig. 9
figure 9

Indian Polar Space Physics Laboratory, Maitri, Antarctica

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8.3 Preservation of original copies of the Constitution of India

One of the other great contributions of CSIR-NPL to the country is the preservation and periodic maintenance of the “Original Copy of the Constitution of India” (both Hindi and English) which is kept and maintained at Parliament Library, New Delhi, [1, 52, 53]. For this purpose, two hermetically sealed glass cases were designed and developed by CSIR-NPL in association with Getty Conservation Institute, USA, to maintain controlled humidity, temperature and oxygen level for the safe and sustained preservation of Calligraphic copies. The “Constitution of India”, written under the chairmanship of Dr. B. R. Ambedkar, was adopted by the Constituent Assembly on November 26, 1949, which was came into force on January 26, 1950. Both the original calligraphed copies are bound in first-class Morocco leather embossed in gold. These copies have great autographic and the original signatures of the founding fathers of the Constitution give them additional historical value. Since 1994, responsibility has been given to CSIR-NPL for the preservation of these prestigious documents.

8.4 Biomedical Metrology

Indian government has recently passed ‘Medical Device Rule 2017’ to administer the quality and conditions of the medical devices being used to support the healthcare sector [54]. It emphasises the requirements to establish the testing and calibration centres for medical devices for implementing and maintaining quality control regulations in Indian healthcare sectors. Using novel biocompatible sensing materials, CSIR-NPL is fabricating indigenous point-of-care devices for the diagnosis of chronic disease, namely heart disease and renal dysfunction to help and support their manufacturers. The calibration and testing facilities for biomedical equipment, viz. the defibrillator machine, defibrillator analyser and the electrical safety analyser, have been established, recently [55].

8.5 Development of Some of the Key Technologies

8.5.1 Development of Hydroelectric Cell [56, 57]

Recently, the development of the hydroelectric cell is a noticeable contribution of the decade. After untiring efforts of 13 years in the laboratory such water driven cell is invented. The realization of the invented cell is achieved through conversion of water into electricity. CSIR-NPL has been granted American and Indian patents for this invention. This water running hydroelectric cell can be used in the laptops, torches, mobile phones etc. and is harmless to the environment because water is being used as fuel. This cell is unique invention in field of green energy. In this cell, lithium substituted magnesium ferrite is used which is abundantly available in India. This material ionizes the water molecule at room temperature. Those ions are being collected at two different electrodes. Thus, due to flow of ions electricity generates. Hydroelectric cell would be a good alternative to the solar cell and fuel cell.

8.5.2 Technology for Converting Waste Plastic into Tiles [58]

India generates approx. 10 million tonnes of plastic waste every year and as per Environment Ministry, nearly 40% of which is not collected back for their safe recycling. In general, this waste plastic is dumped in open space that not only adds unwanted environmental pollution in different forms but also poses serious health hazards to living beings.

Disposal of plastic waste has been a major challenge because of its non-biodegradable nature and it consists of low-density polyethylene. Disposal through burning of these waste plastic bags causes environmental pollution. In this direction, a process technology was developed by CSIR-NPL for useful recycling of plastic waste into designing materials, paver, roof tiles and interlocks, for their rugged and waterproof applications in pathways, gardens, lanes, footpaths, false ceilings etc. This novel transformational technology not only presents a safe disposal of plastic waste but also presents an eco-friendly conversion of plastic waste into useful alternatives, at the same time, to fulfil the societal needs and mitigate environmental problems, caused due to plastic waste. This technology has been well accepted and transferred to several industries and start-ups.

8.5.3 Solar Photovoltaic (PV) System [59]

CSIR-NPL has established the secondary standard facility for efficiency validation of solar cells. A major program is taken up for the establishment of primary standard in collaboration with PTB Germany. India has targeted the PV installations of 100 GW by the year 2022 under the National Solar Energy Mission. CSIR-NPL has a vibrant photovoltaic group in the country with a rich history in silicon based photovoltaics since last four decades. CSIR-NPL has developed silicon solar cells, for the first time in the country, in mid 70’s. CSIR-NPL is the first laboratory to demonstrate the complete process ‘from metallurgical grade silicon to solar grade polysilicon and fabrication of solar cells. Recently, CSIR-NPL has initiated the work on recycling of silicon solar cells/modules.

8.5.4 Methane Emissions

After economic liberalisation of India in the year 1991, the industrial developments started growing manifold with the investment of several multinational companies, which set up manufacturing units in India. This industrial growth also brought the increment in the emission of several pollutant gases out of different sectors like sewage plants, chemical industries, sugar factories, power generation stations, etc. Indian scientists proved the actual methane emissions from the Indian paddy fields is only of the order of 3.46 Tg/year [60, 61] against the controversy over the large methane emission from paddy fields in India (which was earlier estimated as 37.4 Tg/year). This calls for the preparation of methane standard and it was successfully developed by the CSIR-NPL at the time.

8.5.5 Carbon Technologies

The advanced carbon products/materials, magnetic and thermoelectric materials developed at CSIR-NPL are catering the need of the country in the industrial, health, energy as well as strategic sectors like defense, aerospace and nuclear power. Some of the recently developed carbon technologies are, activated carbon, flexible multi wall carbon nanotubes bucky/paper for Li batteries, single layer graphene by CVD, torrefied rice straw pellets for thermal power plants, high density nuclear grade graphite, CNT yarn and CNT based body armour materials to name a few [62].

9 Visitors of CSIR-NPL

The CSIR-NPL has always been the centre of interest, importance, relevance and place of attraction for the visitors from various fields across the globe. During all these years, a list of the world-renowned dignitaries who have visited CSIR-NPL are summarised in Table 3 for science leaders and in Table 4 for political leaders. These visitors include Presidents, Prime Ministers, other Ministers of different countries, Nobel Laureates, Metrologists, Policy makers, etc.

Table 3 Visits of Eminent Science Leaders to CSIR-NPL India
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Table 4 Visits of elected key Representatives/ Political Leaders of India and abroad to CSIR-NPL India at various Occasions/ Events
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10 Conclusion

An illustrated, glorious and magnificent journey of CSIR-NPL, the NMI of India, highlighting its accomplishments from its birth in 1947 to recently celebrated 74th Foundation Day on January 04, 2021, is described and presented in a though concise but exhaustively adequate review report. The establishment of CSIR-NPL as NMI of India and its crucial role in the inclusive growth of the country over the years is outlined, as also highlighted by the Honourable Prime Minister of India in his NPL Foundation Day Speech and Honourable President of India in his Presidential Address of Joint Parliament Session on January 29, 2021. His Excellency mentioned, “Our very own Navigation Satellite System 'NavIC' is also enhancing the prestige of the country. Thousands of fishermen are now benefitting from it. New standards have been set in the form of National Atomic Timescale and Bhartiya Nirdeshak Dravya Pranali, which were dedicated to the nation recently. These indigenous solutions will help in developing Indian products as per international standards”. The journey of contributions to the nation included few milestones, namely development of indelible ink, preservation of original copy of the Constitution of India, solar photovoltaic technology, methane emission, contribution to Indian Antarctica missions etc. The article also includes the pioneering achievements on National Atomic Timescale, Bhartiya Nirdeshak Dravya (BND®)—CRM, foundation of National Environmental Standard Laboratory dedicated to the nation, by the Honourable Prime Minister of India for nation building. A list of galaxy of scientific and political leaders, visionaries who made their visit to this esteemed institution ever since its inception and witnessed its journey as grand national laboratory of India, taking its role beyond the national frontiers, is also summarized at the end. The feature article therefore, would certainly serve as a useful reference document with relevant information, for researchers, scientists, academicians, policy makers, regulators, administrators, industries, stakeholders and science historians, collected at one place.