Legal Metrology (IST) Rules, 2025 | One Nation One Time

Department of Consumer Affairs in collaboration with the Council of Scientific & Industrial Research – National Physical Laboratory (CSIR – NPL) and ISRO, has drafted the Legal Metrology (Indian Standard Time (IST)) Rules, 2025.

  • Objective: Standardize and mandate the adoption of Indian Standard Time (IST) across all sectors, reinforcing the vision of “One Nation, One Time.”
  • Mandatory Adoption of IST: IST, maintained by CSIR-NPL, will be the only legally recognized time standard in India.
    • The use of foreign time references (e.g., GPS time) will be prohibited unless specifically approved by the government.
  • Synchronization of Critical Sectors: All government institutions, financial entities, telecom service providers, power grids, and digital infrastructure must synchronize their systems with IST.
  • Regulatory Framework & Compliance: Compliance will be monitored through periodic audits, and penalties will be imposed for non-adherence.
  • Special Provisions: The rules provide flexibility for strategic and national security applications.
    • Scientific research, astronomy, and navigational applications may use alternative time references with prior government approval.
  • Based on a longitude of 82.5° East, which passes through Mirzapur, Uttar Pradesh.
  • IST is 5 hours 30 minutes ahead of Greenwich Mean Time (GMT), now called Universal Coordinated Time (UTC).
  • Established in 1906, replacing 3 regional time zones from the British era (Bombay, Calcutta, and Madras Time).
  • About: Aims to establish a unified and precise timekeeping framework for all governmental, industrial, technological, and societal applications.
  • Laboratories: The government plans to set up 5 Legal Metrology laboratories across India to achieve microsecond-level accuracy in time dissemination.
  • Need for Self-reliant Timekeeping: India’s reliance on GPS satellites (controlled by the US) poses national security and cybersecurity risks.
  • Function: NPL will utilize atomic clocks to provide accurate time, synchronized via NavIC (Navigation with Indian Constellation).

Source: BS


Previous Year Question

Which one the following countries has its own Satellite Navigation System?

[UPSC Civil Services Exam – 2023 Prelims]

(a) Australia
(b) Canada
(c) Israel
(d) Japan

Answer: (d)


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