India, Jan. 1 -- India's state-backed telecom operator Bharat Sanchar Nigam Ltd. has launched nationwide WiFi calling services, stepping up efforts to retain subscribers and modernise its network against private sector heavyweights.

The new service, effective 1 January 2026, allows users across all telecom circles to make voice calls over WiFi networks without requiring a separate app. The move is designed to plug coverage gaps in "shadow zones", such as high-rise buildings and basements where cellular signals often falter, the company said in a statement.

The rollout serves as a critical stopgap as BSNL races to complete its delayed 4G deployment. The carrier has now commissioned approximately 97,000 4G sites using an indigenous techno...