Flight operations at Indira Gandhi International airport in New Delhi were partially affected on Friday after the air traffic control tower witnessed power failure.
Screens of the air traffic control officers (ATCOs) went blank at 12.20 pm when power supply was disrupted, sources said.
Though the standby power took over the system within seconds, it took over 45 minutes to reboot entire consoles and restore the operations fully, they said.
The operations were partially affected as ATCOs held the departures, but flights departed in a controlled way while there was no disruption in incoming flights, they said, adding since the traffic was low, it did not pose any major problem.
The ATCOs had to handle the flight manually initially.
The IGI airport is run by the Delhi International Airports Limited but the operations at the ATC tower are under the control of the Airports Authority of India (AAI), the country's government-owned airport operator.
Asked about it, AAI spokesperson G S Bawa said at around 12.21 pm there was a power failure but standby power took over, which worked for around 10 minutes till 12.31 pm, after which power was restored and there was no disruption.
"The ATC was allowing departures in controlled manner while there was no disruption in flights arriving here," he said.