On the evening of November 6, 2025, a failure in the Automatic Message Switching System (AMSS) at Delhi’s Indira Gandhi International Airport triggered a massive disruption. The AMSS is a critical data-routing network used by air-traffic control (ATC) to automatically send and receive flight-plan messages, weather updates and routing instructions.

When the AMSS went offline, air-traffic controllers were forced to revert to manual processing—writing and coordinating flight plans by hand, a far slower procedure at an airport managing over 1,500 daily movements (~60 per hour in peak). Because every arrival and departure relies on seamless data flow, queues built up on runways and in terminals, airports nationwide felt the cascading impact. By some counts, more than 800 flights were delayed and several were cancelled.

The Airports Authority of India confirmed the system is now functioning but noted that residual delays will persist as the backlog clears. Airlines are advising passengers to check status updates and factor in extra time.