NEW DELHI: Operations at Delhi’s Indira Gandhi International (IGI) Airport have returned to normal, the airport authority said on Saturday, a day after a technical glitch in the Air Traffic Control (ATC) flight planning process caused widespread delays across more than 800 flights. In an advisory issued at 11:55 hours, IGI Airport confirmed that all flight operations were now normal. “Airline operations at Delhi Airport are returning to normal, and all concerned authorities are working diligently to minimise any inconvenience caused. Passengers are advised to stay in touch with their airlines for the latest flight update,” the advisory stated.The disruption at Indira Gandhi International Airport (IGIA) was triggered by a glitch in the Automatic Message Switching System (AMSS), which forced air traffic controllers (ATC) to abandon automated operations and switch to manual procedures. The slowdown began to affect the entire network from Thursday afternoon.As the airport deals with the fallout, it was revealed that, in July, the Air Traffic Controllers’ Guild of India had warned that “current systems, particularly at major airports such as Delhi and Mumbai, have shown performance degradation, including slowness and system lags, affecting operational efficiency and safety margins.”Read more: System crash, flight disruptions could have been avoided, say Air Traffic ControllersThe AMSS is responsible for transmitting flight plan data to controllers’ screens, and its failure meant that each flight had to be processed manually, causing significant delays in arrivals and departures. As India’s busiest airport, IGIA typically handles around 1,500 aircraft movements daily, with peak traffic reaching 60–70 flights per hour, leaving little room for disruption when automation fails. Air traffic control, a ground-based service, manages and guides the movement of aircraft both on the ground and within controlled airspace, making such technical failures particularly impactful.