Air India cancels all March 21 flights to and from London's Heathrow Airport amid massive power outage

Air India has cancelled all its flights to and from London Heathrow Airport on March 21 following a massive power outage caused by a fire at an electrical substation near the airport.

"Due to a significant power outage, London Heathrow Airport has been shut down until 23:59 on 21st March. All Air India flights to and from London Heathrow for 21st March have been cancelled,” the airline said on X.

Air India said that one flight on its way to Heathrow is returning to Mumbai, another has been diverted to Frankfurt.

The airline also said that its flights to London Gatwick remain unaffected.

Earlier, Heathrow Airport, one of the world’s busiest, announced the shutdown, urging passengers not to travel to the airport and contact their airline instead for further information.

“Due to a fire at an electrical substation supplying the airport, Heathrow is experiencing a significant power outage. To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23:59 on 21 March.”

The disruption is expected to be massive, with flight tracking service FlightRadar24 estimating that at least 1,351 flights to and from Heathrow will be cancelled today.

According to aviation analytics firm Cirium, Air India has 6 flights to LHR on March 21, with a total of 1,843 seats.

British Airways has 8 flights per day between India and LHR, including 3 from Mumbai and 2 from Delhi. Virgin Atlantic has 5 daily flights to LHR from Delhi, Mumbai and Bengaluru.

Cirium said roughly upwards of 1,45,000 passengers could be impacted.

"This is an estimate based on the daily total scheduled seats and flights, which will not be full, and noting the various departure times around the world that could arrive at LHR on Friday. On the LHR departures front, upwards of 145,000 total seats are scheduled to fly on March 21.

"There are 669 flights scheduled to depart on March 21, 2025," it said.

The outage occurred due to a fire at a substation located about a mile and a half north of the airport in Hayes, where half of a transformer continues to burn.

The London Fire Brigade has deployed ten fire engines and at least 70 firefighters to tackle the blaze.

Scottish and Southern Electricity Networks reported that over 16,300 homes have lost power. The energy supplier has urged anyone medically dependent on electricity to contact them for support.

The cause of the fire remains unclear.