The Department of Consumer Affairs has notified the Legal Metrology (Indian Standard Time) Rules, 2026. Indian Standard Time (UTC+5:30) becomes the compulsory time reference for legal, administrative, commercial and official use. The national time scale, UTC(NPLI), is maintained by CSIR-National Physical Laboratory, New Delhi, and official IST will be spread through Regional Reference Standards Laboratories and NavIC. Telecom, digital payment and power-grid networks must synchronise using NTP and PTP. The rules take effect 180 days after Gazette publication, around March 2027, with penalties under the Legal Metrology Act, 2009.