New Delhi, Nov. 30 -- On Friday the department of telecommunications (DoT) asked companies that own messaging apps such as Whatsapp, Signal, Telegram and others not to allow users without active SIM cards in their phones to use these apps.

Why has the DoT done this now, and what does it mean for the future of these widely used platforms?

In a letter dated 28 November, DoT asked the companies that own the messaging apps WhatsApp, Telegram, Signal, Arattai, Snapchat, Sharechat, Jiochat, and Josh to ensure that their services remained linked to users' SIM cards and phone numbers. This means a user without an active SIM card in their phone should not be able to use these apps.

Companies must also ensure that users are automatically logged ...