Dozens of flights were delayed at the Indira Gandhi International (IGI) Airport on Monday, as a thick blanket of fog engulfing the national capital affected visibility.
Hundreds of passengers were stranded at the airport.
"Due to the foggy conditions the runway visibility dropped to less than 300 meters and affected both departures and arrivals," said an airport official.
"Though we don't have the exact number of flights disrupted, over a dozen must have faced problems due to foggy conditions (Monday morning)."
By 9 a.m., the runway visibly had improved to 500 meters and over 40 flights had taken off from the airport, he added.
The fog affected motorists in the morning rush hour as well.