Hundreds of flights were cancelled or delayed after the Hartsfield-Jackson Atlanta international airport, the world’s busiest, suffered a power outage on Sunday, Reuters reported. Georgia Power, the facility that provides electricity to the airport in the United States, attributed the outage to a fire in a underground electrical station which damaged substations serving Hartsfield.

Passengers were left stranded inside terminals or in aircraft during a partial shutdown of the airport. Several shared images and videos from the facility on social media.

However, all passengers had safely disembarked aircraft, Atlanta Mayor Kasim Reed said around 10 pm Eastern Standard Time (8.45 pm Indian Standard Time). Power was finally restored at 11.45 pm Eastern Standard Time (10.15 am IST).

Georgia Power said the fire also damaged access to a power backup system. The company said it would investigate the cause of Sunday’s fire and prevent recurrences.

Atlanta Airport’s official Twitter handle said that meals were being provided to over 5,000 passengers, and that trains ferrying commuters to and from the airport would soon be operational.

Several airlines including United, Southwest and American Airlines ordered a suspension of operations on Sunday.

The airport handles an average of more than 2,50,000 passengers and almost 2,500 flights every day, BBC reported.