New Delhi: The flights were delayed as the runway visibility dropped to less than 50 metres, bringing landing and take-off to a halt for over an hour, an airport official said.
This is the first fog of the winter season, which started to descend at the airport early in the morning.
The flights, scheduled around 5 AM, were disrupted as visibility on all the three runways were below 50 metres, airport officials said.
Around 40 domestic and international flights, arriving and departing from Delhi, were delayed by up to two to three hours. Some arriving flights were diverted while two were cancelled.
The fog started to become dense around 5 AM and the visibility went below 50 metres, the minimum required for landing under poor visibility conditions using the CAT-III B instrument landing system (ILS).
The minimum visibility for an aircraft to take off under low visibility conditions are between 125 to 150 metres, depending on the size of the plane.
Yesterday, schedules of around 140 flights were badly affected after Delhi witnessed the winter's first fog. Nine flights were diverted while eight were cancelled.
According to railway officials 71 trains were running late.
