The Indian airports authority said late on Friday that a system used to generate flight plans was "up and running", more than a day after a technical glitch led to delays of hundreds of flights at Delhi airport, one of the world's busiest.
The malfunction delayed departures and arrivals, with the disruptions expected to spill over into Saturday.
The Airports Authority of India (AAI) said it will take some time for the system to resume functioning normally, given the huge backlog.
At least 200 flights were delayed on Friday after the system started malfunctioning at around 6:00 PM the previous day, a source familiar with the matter had told Reuters.
"The issue was detected... in the IP-based Automatic Message Switching System (AMSS)." AAI said in a post on X, without providing details on the cause of the technical issue.
Shortly after the AAI announcement, IndiGo, which has a 60 per cent share in India's domestic aviation market, confirmed on social media platform X that its operations at airports in Delhi and other parts of northern India were gradually returning to normal.
The malfunction in the AMSS, used to generate flight plans, forced controllers to develop them manually, leading to delays, the AAI said earlier on Friday.
Some airlines, such as Air India Express, deputed their own personnel to air traffic control to generate flight plans manually, a second source familiar with the matter said.
The incident follows a ransomware attack that disrupted some of Europe's biggest airports, knocking out automated check-in systems and affecting flights in September.
Delhi airport handles 60-70 aircraft movements per hour. Data from Flightradar24 showed the average departure delay was 60 minutes on Friday evening.
The malfunction also hit several international airlines, with an ITA Airways flight to Rome delayed by nearly two hours and a Virgin Atlantic flight to London by more than an hour.
Delhi airport handled about 78 million passengers in 2024, making it the ninth busiest airport in the world, according to Airports Council International.
The operator of the airport is majority owned by GMR Airports, while air traffic control is managed by the AAI.
Update on Technical Fault at IGI Airport, New Delhi
— Airports Authority of India (@AAI_Official) November 7, 2025
NEW DELHI, November 7, 2025 - AAI at Indira Gandhi International Airport addressed a technical issue in the Automatic Message Switching System (AMSS), which caused delays in processing flight plan messages. The issue was…
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