Here Come ‘One Nation, One Time’ Rules

September 5, 2026

In a bid to develop modern digital and critical infrastructure, the government has notified the Legal Metrology (Indian Standard Time) Rules, 2026 — marking a significant step towards establishing Indian Standard Time (IST) as the common, legally recognised and traceable time reference for the country. The rules comes into force 180 days from the date of their publication in the Official Gazette.

The initiative supports the government’s vision of “One Nation, One Time”, ensuring that critical sectors and digital systems across the country operate with a common and reliable time reference. The rules provide a comprehensive framework for the generation, maintenance, dissemination and use of IST. Telecommunications, financial transactions and digital payments, power grids, transportation, data centres, government information systems and other critical services depend on accurate time synchronisation and reliable time stamps.

A common national time reference also has an important cybersecurity dimension. Accurate time stamps are essential for correlating events across multiple systems during cyber incidents and for effective security monitoring. The CERT-In Guidelines on Information Security Practices for Government Entities, 2023, recommend synchronisation of ICT systems with standard time sources including NPL and NIC.

Recognising that making IST a legal reference must be accompanied by adequate availability and geographical reach of traceable time, CSIR-NPL, ISRO and the Department of Legal Metrology under the MoCA jointly established secondary timescales at five Regional Reference Standard Laboratories (RRSLs) located at Ahmedabad, Bengaluru, Bhubaneswar, Faridabad and Guwahati.

These secondary time scales are continuously traceable to IST maintained by CSIR-NPL, thus creating a distributed national architecture for reliable dissemination of IST. Moreover, CSIR-NPL also provides traceability of IST to ISRO for the NavIC system, enabling satellite-based dissemination of Indian Standard Time and strengthening the availability and resilience of national timing services.

IST can be disseminated through network-based technologies such as NTP and PTP, and satellite-based systems including NavIC. High-precision optical fibre-based technologies such as White Rabbit are also being tested. This distributed architecture provides flexibility for users ranging from ordinary ICT systems to applications requiring highly precise time and frequency synchronisation.