Air India was caught up in UK air traffic chaos on Tuesday after a technical failure at NATS disrupted flight operations across the country.

The outage triggered more than 1,000 flight cancellations in the UK on Tuesday, with 177 more flights cancelled for Wednesday.

Heathrow, a key hub for India-UK travel, was among the hardest-hit airports, alongside Gatwick, London City, Luton, Edinburgh and Bristol.

Air India confirmed the technical problem forced it to divert, delay or cancel multiple flights scheduled to and from UK airports.

NATS said its systems were operating normally again, but warned that recovery from the backlog across the aviation network would take time.

Heathrow, Gatwick, London City, Luton, Edinburgh and Bristol airports all reported disrupted flight operations during the outage, with Heathrow the most severely affected.

NATS said recovery from the backlog across the aviation network would take time even after the underlying technical issue was resolved.

This is not the first time a NATS technical failure has caused mass disruption to UK air travel, with similar system outages having grounded flights in the past.

Air India was among several international carriers, alongside UK domestic airlines, affected by the disruption at Heathrow and other British airports.

Passengers travelling to and from the UK were advised to check their flight status directly with airlines given the scale and unpredictability of the disruption.

NATS, formerly known as National Air Traffic Services, is the primary air traffic control provider for UK airspace, handling flight data processing for arrivals and departures across the country’s busiest airports.

September is a peak month for Indian student travel to the UK, meaning the timing of the outage was particularly disruptive for passengers flying to British universities for the new academic term.

NATS chief executive Martin Rolfe said the exact cause of the technical failure was still being investigated, though the system was confirmed to be operating normally again after the fix.

London Heathrow Airport Terminal 5, Wikimedia Commons, CC0

Nearly 3,000 flights were delayed across Asia on Tuesday as ash from the erupting Mount Anak Krakatau volcano disrupted regional air travel, including at Delhi and Mumbai.

The region-wide toll stood at 2,927 delays and 584 cancellations, spanning airports in India, Japan, China and Indonesia.

Delhi’s Indira Gandhi International Airport logged 177 delays and 4 cancellations; Mumbai’s Chhatrapati Shivaji Maharaj International Airport logged 245 delays and 3 cancellations.

IndiGo recorded 258 delayed flights and 9 cancellations, while Air India recorded 114 delays and 2 cancellations.

Mount Anak Krakatau, in the Sunda Strait, began erupting on September 4 and remains at Alert Level III as of the latest assessment.

As of September 7, Indonesian volcanological authorities kept Anak Krakatau at Alert Level III, warning that the risk of further eruptions remained high and that airports were reopening in phases rather than all at once.

Etihad Airways and SpiceJet were among the international and domestic carriers reporting delays on services to and from Delhi and Mumbai during the disruption.

Volcanic ash poses a direct safety hazard to jet engines, which is why aviation authorities impose ground restrictions and altitude diversions rather than allowing aircraft to fly through affected airspace.

Garuda Indonesia and Batik Air, the two largest carriers based in the affected region, reported the heaviest cancellation rates of any airline tracked in the disruption.

Airlines advised passengers travelling through affected hubs to check flight status directly with carriers before heading to the airport, as ash-related restrictions were being updated through the day.

Mount Anak Krakatau, in Indonesia’s Sunda Strait, began erupting on September 4, triggering a five-day aviation shutdown that closed eight Indonesian airports and stranded more than 270,000 passengers.

Jakarta’s Soekarno-Hatta International Airport recorded the highest number of cancellations in the region, with 207 flights called off as ash plumes drifted over the airspace.

Interior of Terminal 3, Indira Gandhi International Airport, Wikimedia Commons, CC0

IndiGo has announced daily flights between Mumbai and Dar es Salaam, Tanzania, expected to begin in November.

The route connects Chhatrapati Shivaji Maharaj International Airport in Mumbai with Julius Nyerere International Airport in Dar es Salaam.

IndiGo enters a market already served nonstop by Air Tanzania, which operates the route using Boeing 787 aircraft.

The launch makes Dar es Salaam IndiGo’s second continental African destination and fourth overall including Mauritius and Seychelles.

IndiGo has described the move as part of a strategy to add capacity in underserved markets with strong passenger demand.

IndiGo’s wider international expansion this period also includes new Mumbai-Hanoi flights starting October 25, even as it winds down Chennai-Reunion service and suspends London Heathrow operations.

The airline has also returned six leased Boeing 787 aircraft as part of a broader restructuring of its long-haul international fleet.

IndiGo’s strategy has been described as adding capacity where it identifies strong passenger demand and opportunities to connect underserved markets, rather than pursuing uniform network growth.

India-Tanzania trade and tourism ties have grown steadily in recent years, with East Africa emerging as a market Indian carriers have increasingly targeted for direct connectivity.

IndiGo has expanded aggressively into international markets over the past two years, adding a steady stream of new long-haul and mid-haul routes even as it manages fleet and staffing constraints on the domestic side.

Dar es Salaam will become IndiGo’s second continental African destination and its fourth market across Africa and nearby islands, alongside existing services to Mauritius and Seychelles.

IndiGo will compete directly with Air Tanzania on the Mumbai-Dar es Salaam sector, where the Tanzanian flag carrier currently operates using Boeing 787 aircraft.

The Indian High Commission in Tanzania has confirmed IndiGo’s plans for daily Mumbai-Dar es Salaam flights, though the airline’s own timeline has shifted from an initially discussed October start to November.

Photo of an IndiGo Airbus A321, Wikimedia Commons, CC BY-SA 4.0