Flight operations at Delhi’s Indira Gandhi International Airport (IGIA), the busiest in India, faced major disruption starting November 6, 2025, due to a technical fault in the Automatic Message Switching System (AMSS), essential for relaying flight plans and operational messages between air traffic control and airlines. The AMSS system, based on IP technology and provided by Electronics Corporation of India Limited (ECIL), is a vintage system designed to support up to 128 channels, crucial for communication within the ATC network. ECIL, a government-owned entity, is known for supplying such critical infrastructure, but this incident has raised concerns over the reliability and upkeep of their systems. The problem possibly emerged amid challenges in simultaneously managing upgrades for both the AMSS and the Instrument Landing System (ILS) to Cat III, creating prioritization conflicts that delayed necessary software patches. This prioritization delay contributed to the AMSS failure, forcing air traffic controllers to manually process flight data, drastically slowing operations and delaying over 800 flights. The Airports Authority of India (AAI) engaged ECIL officials and OEM teams to restore service, normalizing operation by late evening on the day of the incident. An inquiry is underway to fully ascertain root causes and prevent recurrence.