Flight operations were disrupted for the second consecutive day on Wednesday as the airport was in the grip of a dense fog for over three hours on Wednesday morning.
Over two dozen flights coming to and leaving Delhi were delayed as Runway Visibility Range (RVR) at the Indira Gandhi International Airport dipped below 100 meters between 5:30 am and 9:00 am making it impossible for carrying out any flight activities, airport sources said.
"Fog set in at 2:00 am with general visibility and RVR declining at a steady rate," RK Jenamani, Director of Meteorological Department at the airport said.
"There was zero visibility between 5:30 am and 9:00 am," he said adding that fog dispersal was quick as the sun ascended in the eastern skies.
Jenamani said the runway visibility had improved to 1000 meters by 10:00 am.
Prime Minister Manmohan Singh departed on a four-day visit to Japan in a special aircraft that took off at 10:15 am in clear weather conditions.
At least a dozen Indian Airlines (IA) flights were delayed due to fog, IA sources said.
The CAT III B instrument landing system was activated at the airport at about 5:30 am as dense fog gathered on the runway.
A few Indian Airlines flights and some international flights could land in the dense fog using the CAT III B instrument landing system in near-zero visibility conditions.