UPSC Prelims Practice Questions — Legal Metrology (Indian Standard Time) Rules, 2026 Notified: Major Step Towards “One Nation, One Time”

Q1. Consider the following statements regarding the evolution of Indian Standard Time as a uniform time reference: 1. The meridian of 82°30′ E, passing near Mirzapur, was announced as the basis of Indian Standard Time by Viceroy Lord Curzon. 2. Indian Standard Time was formally adopted by the British authorities with effect from 1 January 1906. 3. Calcutta continued to keep its own local time and shifted to Indian Standard Time only in 1948. 4. Bombay was the earliest of the presidency capitals to abandon its local time, switching to Indian Standard Time well before Calcutta did. Which of the above is/are NOT correct?

  1. The meridian of 82°30′ E, passing near Mirzapur, was announced as the basis of Indian Standard Time by Viceroy Lord Curzon.
  2. Indian Standard Time was formally adopted by the British authorities with effect from 1 January 1906.
  3. Calcutta continued to keep its own local time and shifted to Indian Standard Time only in 1948.
  4. Bombay was the earliest of the presidency capitals to abandon its local time, switching to Indian Standard Time well before Calcutta did.
  • A. 1 and 2
  • B. 3 only
  • C. 4 only
  • D. 2 and 4

Q2. Which one of the following was the principal consideration behind fixing India's standard time at a half-hour rather than a whole-hour offset from Greenwich?

  • A. It was a midpoint between the two whole-hour zones proposed for India, adopted in place of a two-zone scheme
  • B. It corresponded to the local mean time of Calcutta, then the capital of British India, which was retained as the national standard
  • C. It matched the timetable reference already used by the railways at Bombay, which was extended to the whole of British India
  • D. It was fixed so as to keep India's clocks aligned with the standard meridian adopted by neighbouring Nepal

Q3. Which one of the following best describes the regulatory scope of the Legal Metrology Act, 2009?

  • A. Regulation of trade and commerce in goods sold or distributed by weight, measure or number, and of the instruments used for such transactions
  • B. Regulation of every scientific measurement carried out in India, including all research laboratory calibration, to the exclusion of any other authority
  • C. Formulation and mandatory certification of quality standards for all manufactured products offered for sale anywhere in India
  • D. Regulation of all contracts that specify any quantity, including services priced by units of time, in every sector without exception

Q4. The Legal Metrology Act, 2009 was enacted as a unified law consolidating and repealing which one of the following pairs of earlier enactments?

  • A. The Standards of Weights and Measures Act, 1976 and the Standards of Weights and Measures (Enforcement) Act, 1985
  • B. The Standards of Weights and Measures Act, 1956 and the Bureau of Indian Standards Act, 1986
  • C. The Standards of Weights and Measures (Packaged Commodities) Rules, 1977 and the Consumer Protection Act, 1986
  • D. The Indian Weights and Measures of Capacity Act, 1871 and the Essential Commodities Act, 1955

Q5. Under the 'One Nation, One Time' project that underpins the Legal Metrology (Indian Standard Time) Rules, Indian Standard Time is to be disseminated to users from how many Legal Metrology laboratories across the country?

  • A. Three
  • B. Five
  • C. Eight
  • D. Twelve

Q6. Which one of the following correctly states the core obligation created by the Legal Metrology (Indian Standard Time) Rules?

  • A. Legal, administrative and commercial activities must be synchronised with IST, and other time references are barred unless expressly permitted
  • B. A second standard time is notified for the eastern States, so that two legally valid time references operate simultaneously in the country
  • C. A season of daylight saving is to be observed for a fixed annual period, uniformly across all States and Union Territories
  • D. Packaged commodities must carry the time of packing in IST alongside the declarations of month and year of manufacture

Q7. The National Primary Timescale maintained at CSIR-NPL, from which Indian Standard Time is realized, is generated from an ensemble of how many atomic clocks?

  • A. Four — three caesium clocks and one active hydrogen maser
  • B. Five — caesium clocks alone, without any hydrogen maser
  • C. Seven — five caesium clocks and two active hydrogen masers
  • D. Nine — six caesium clocks and three active hydrogen masers

Q8. With reference to the institutional architecture of the 'One Nation, One Time' initiative, consider the following statements: 1. Indian Standard Time is realized and maintained by CSIR-National Physical Laboratory, which is the National Metrology Institute of India. 2. The time dissemination project is being implemented by the Department of Consumer Affairs in collaboration with CSIR-NPL and ISRO. 3. Regional Reference Standard Laboratories at Ahmedabad, Bengaluru, Bhubaneswar, Faridabad and Guwahati are being equipped with atomic clocks and secure synchronisation systems for this purpose. 4. Under the project ISRO replaces CSIR-NPL entirely, becoming the sole custodian of India's national time standard. Which of the statements given above is/are correct?

  1. Indian Standard Time is realized and maintained by CSIR-National Physical Laboratory, which is the National Metrology Institute of India.
  2. The time dissemination project is being implemented by the Department of Consumer Affairs in collaboration with CSIR-NPL and ISRO.
  3. Regional Reference Standard Laboratories at Ahmedabad, Bengaluru, Bhubaneswar, Faridabad and Guwahati are being equipped with atomic clocks and secure synchronisation systems for this purpose.
  4. Under the project ISRO replaces CSIR-NPL entirely, becoming the sole custodian of India's national time standard.
  • A. 1 and 2 only
  • B. 2, 3 and 4
  • C. 1, 2 and 3
  • D. 3 and 4 only

Q9. Consider the following statements comparing the notified Legal Metrology (Indian Standard Time) Rules with the position that obtained before them: 1. The notified rules do away with every exemption, so that scientific, astronomical and navigational activities too must use Indian Standard Time without exception. 2. Government offices and public institutions are required to adopt reliable synchronisation protocols such as the Network Time Protocol and the Precision Time Protocol. 3. Compliance is to be monitored through periodic audits, with penalties for violations. Which of the statements given above is/are correct?

  1. The notified rules do away with every exemption, so that scientific, astronomical and navigational activities too must use Indian Standard Time without exception.
  2. Government offices and public institutions are required to adopt reliable synchronisation protocols such as the Network Time Protocol and the Precision Time Protocol.
  3. Compliance is to be monitored through periodic audits, with penalties for violations.
  • A. 1 only
  • B. 1 and 2 only
  • C. 2 and 3 only
  • D. 1, 2 and 3