New Delhi, Feb 8 (IANS): A failure in power supply to the radar systems of the Indira Gandhi International Airport (IGIA) here late afternoon delayed several flights Friday.

"There was a minor power failure in the radar systems. The radars that time still functioned on backup power source, till the time main power supply was available," an Airports Authority of India (AAI) official told IANS.

"All systems were functioning properly and there was even a second backup power source available. However, during this time period of main power supply failure, we had to maintain a controlled departure and arrival slot system, as a precaution."

The radar systems, used by air traffic controllers at the Delhi airport, are under the communication, navigation and surveillance (CNS) cadre of the AAI, while the rest of the airport operations are managed by GMR Group company Delhi International Airport Limited (DIAL).

An official with a major Indian domestic carrier confirmed to IANS that there were major delays for about 20-25 minutes around 12.15 p.m.

"We had four domestic flights delayed due to this. The traffic movements was restored after we got clearance from the ATC (air traffic control)."

Delhi airport is one of the busiest in the country and handles around 800 arrivals and departures per day.