Major ATC glitch paralyses Delhi airport, over 500 flights delayed across airlines

Flight operations at Delhi’s Indira Gandhi International Airport have been thrown into chaos after a major technical fault crippled the airport’s Air Traffic Control (ATC) system, resulting in more than 500 flights getting delayed between Thursday (November 6) evening and Friday (November 7) morning.

According to Flightradar24 data, average departure delays reached around 50–55 minutes, with some departures held up by more than an hour.

By late morning Friday, airlines and airport officials still could not confirm when the core technical fault would be fixed, raising the risk of cascading disruptions throughout the day and across other airports in the region.

Passengers are stranded in terminals and on runways, with major carriers, including Air India, IndiGo, SpiceJet, and Akasa Air, warning travellers to expect extended delays as technical teams scramble to restore normalcy. International airlines have also issued advisories as Delhi airport is a major transit hub.

What brought airport to a halt

The disruption began late Thursday and intensified by Friday morning, as the airport’s crucial Automatic Message Switching System (AMSS), a backbone for managing and relaying real-time flight data to the ATC-suffered a major outage. The AMSS system was developed and managed by the Airports Authority of India (AAI) for Delhi Airport and other major Indian airports.

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This system helps manage flight information, air traffic control, and passenger information across multiple airports in the country. And when it tanked, it forced air traffic controllers to process every departure and arrival manually, replacing what is normally a seamless, automated flow with a slow and error-prone system.

With more than 1,500 flights typically handled every day, Delhi airport quickly outstripped its capacity to manage the congestion, resulting in huge queues on the ground and snarls in the sky.

Air India issues advisory

“A technical issue with the ATC system in Delhi is impacting flight operations across all airlines, leading to delays and longer wait times at the airport and onboard aircraft. We regret the inconvenience caused by this unforeseen disruption, which is beyond our control, and appreciate your patience,” stated Air India in a post on X.

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“Our cabin crew and on-ground staff at the airport are extending immediate assistance to reduce passenger inconvenience. We request you to check your flight status before heading to the airport,” it added.

Air India further assured passengers that “the system has since been restored” in part, but warned that “some of our flights may continue to be delayed for some time as the situation normalises progressively.” The carrier’s teams promised support for those affected.

Impact across network, says IndiGo

IndiGo, India’s largest carrier, said its Delhi operations were significantly affected. “Flight operations at Delhi Airport are currently experiencing delays due to a technical issue with the Air Traffic Control (ATC) system. As a result, flight operations at Delhi and several northern regions are impacted. We understand that extended wait times, both on the ground and onboard, may cause inconvenience, and we sincerely appreciate your patience,” IndiGo said in its official X statement.

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Other airlines, such as SpiceJet and Akasa Air, also notified travellers about the delays, urging them to check flight statuses before coming to the airport and brace for protracted wait times.

‘Controllers processing manually’: AAI

AAI, responsible for managing nationwide air traffic, explained the root cause in a statement: “Flight operations at Delhi Airport are experiencing delays due to a technical issue in the AMSS, which supports Air Traffic Control data. Controllers are processing flight plans manually, leading to some delays. Technical teams are working to restore the system at the earliest. We appreciate the understanding and cooperation of all passengers and stakeholders.”

While the automatic network outage is a rare event, aviation sources suggest it may have been triggered by a software malfunction or even a potential malware incident, as investigations continue.

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Delhi’s airport consistently ranks among the top 10 busiest airports globally by total passenger traffic. For the year 2024, it was ranked 9th in the world, handling approximately 77.8 million passengers.

Monthly traffic statistics show it can handle over 7 million passengers in peak months such as December 2024 and January 2025; and as an international gateway, it regularly facilitates anywhere between 670,000 to 700,000 transit passengers between Asia and Europe in a given year. So this current issue is expected to ripple beyond Delhi and have a widespread impact on aviation networks in India and abroad.

Airport at breaking point

At ground level, the crisis led to huge passenger backlogs, with scenes of long queues winding through check-in and security. Some travellers reported being stuck in planes on the tarmac, while pilots and crew relayed repeated updates about unpredictable departure times.

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As the airport’s capacity buckled under the slowdown, officials acknowledged the terminal’s parking and holding areas were stretched, with “not enough space for all the planes,” risking further gridlock for arriving international and domestic flights.

A spokesperson for the Delhi International Airport Limited (DIAL) said, “Due to a technical issue with the ATC system, flight operations at IGIA are experiencing delays. Our team is actively working with all stakeholders to resolve it at the earliest.”

Passengers urged to hold off travel

Several international airlines are intensifying advisories, urging customers to “check flight status before leaving for the airport” and expect “longer wait times at the airport and onboard aircraft.” The Directorate General of Civil Aviation (DGCA India), too, has advised that delays may continue through the day as manual operations persist.

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Global carriers such as Emirates, British Airways, and Singapore Airlines have notified their passengers of potential delays. The airlines have said that they are closely monitoring the situation as updates come in from Indian aviation authorities.