Legal metrology and time traceability Legal Metrology Indian Standard Time Rules 2026: What Traceable IST Means for Industry Updated: 13 September 2026 Short answer: India notified the Legal Metrology (Indian Standard Time) Rules, 2026 on 27 August 2026. The rules were published in the Official Gazette on 29 August and come into force after a 180-day transition period. They establish Indian Standard Time as the common reference for legal, administrative, commercial and other official purposes, while building a traceable national timing framework around CSIR-NPL, authorised timing sources and Indian dissemination infrastructure. Time looks simple when it is shown on a wall clock. It becomes a measurement problem when thousands of systems must agree on exactly when an event occurred. Financial transactions, telecommunications networks, power systems, transport infrastructure, computer logs and digital government services all depend on times...