The Indian government is making SIM binding compulsory for WhatsApp users in the country, and this rule could significantly change how you use your account across devices. Starting March 1, 2026, the Department of Telecommunications (DoT), under the Telecom Cyber Security (TCS) Rules, 2024, will enforce mandatory SIM binding. In simple terms, your WhatsApp account will have to remain linked to the physical SIM card inserted in your primary phone.