Operations at the Indira Gandhi International Airport in New Delhi on Saturday remained unaffected even as the airport witnessed fog in the early hours.
Only one flight was delayed due to weather at Delhi.
However, 15 flights were delayed and another five cancelled due to operational reasons and bad weather at destination, an airport official said.
Fog started to descend at the airport around midnight and runway visibility dropped to 25 metres around 2 a.m. on the third runway.
Visibility dropped to 225 metres on the main runway around 3 a.m. and remained so for about an hour after which started to improve on both the runways.
Runway visibility improved to more than 2,000 metres on the main runway by 5.20 a.m. and on third runway from 5.50 a.m., so there was no affect on operations as most of the domestic departures begin from 6 a.m., they said.
