Exclusive | Why India is making IST legally enforceable: An expert explains

India has used Indian Standard Time (IST) for many years. The new Legal Metrology (Indian Standard Time) Rules, 2026 make IST a legally enforceable reference for official and commercial use, requiring various sectors to synchronize their systems to time traceable to IST. Poonam Arora, Scientist G and Head of the Time & Frequency Metrology Division at the CSIR-National Physical Laboratory (NPL), explained the significance of this change.

Under current laws, IST has been maintained and disseminated by CSIR-NPL, which is mandated to maintain the country's scientific standards. However, before these rules, IST did not have legal status, meaning organizations could not enforce a requirement for time to be traceable to IST.

To become traceable to IST, a computer's time must come from a trusted source, such as a Network Time Protocol (NTP) server. The default server may be abroad, leading to potential discrepancies. With IST becoming legally enforceable, organizations must synchronize their time settings with IST to avoid any issues.

The required accuracy for time synchronization depends on the specific application. For example, ISRO requires nanosecond-level accuracy, while CSIR-NPL maintains the country's time within a few nanoseconds of the international reference, UTC. For most everyday applications, millisecond-level accuracy provided by NTP is sufficient.

Organizations will need to ensure their systems are synchronized with IST, either by using NTP servers like those operated by NPL, NIC, or Regional Reference Standard Laboratories (RRSLs). Displaying other time zones is permissible as long as IST remains the reference.

Overall, this new legislation aims to establish IST as the common national time reference, which can improve cybersecurity, reduce crime, and make critical infrastructure more resilient.