Legal Metrology (Indian Standard Time) Rules, 2026 Notified
Why in the news
The Centre has notified the Legal Metrology (Indian Standard Time) Rules, 2026, making Indian Standard Time (IST) the legally recognised time reference for the country under the ‘One Nation, One Time’ idea.
Key facts
- Nodal body: Legal Metrology Department, Ministry of Consumer Affairs, Food and Public Distribution.
- Effective 180 days after publication in the Official Gazette.
- CSIR-NPL, India’s National Metrology Institute, maintains the primary IST timescale.
- ISRO provides NavIC based time dissemination.
- Five Regional Reference Standard Laboratories (Ahmedabad, Bengaluru, Bhubaneswar, Faridabad, Guwahati) keep secondary timescales.
How time is delivered
| Method | Type |
|---|---|
| NTP, PTP | Network-based |
| NavIC | Satellite-based |
| White Rabbit | Optical fibre (reported to be in testing) |
Why it matters
A synchronised time reference matters for banking and payment timestamps, power grids, railways, airports, telecom and cybersecurity. The rules aim to lessen dependence on foreign satellite timing sources.
Exam angle
- Link IST, CSIR-NPL and NavIC together.
- Rules fall under the Ministry of Consumer Affairs.
- Number to remember: 180 days.