After four days of disruption due to thick fog, flight operations were normal at the Indira Gandhi International airport here this morning.

"Flight operations went on smoothly despite a shallow fog in the morning as the runway visibility remained over 1,500 metres for the main runway while it was over 1,200 metres for the new runway," an airport official said.

The runway visibility remained over 1,000 metres for main runway through out last night and this morning, though the visibility dipped to a low of 400 metres on the new runway but it was for just half-an-hour and it does not cause any delay, he said, adding the operations during the day remained smooth.

However, few domestic -- inbound and outbound -- flights to Srinagar, Amritsar, Jaipur, Chandigarh, Dibrugarh and Guwahati were delayed due to bad weather conditions in those cities or due to some operational reasons.

Also about 10 international flights arrived late in the national capital which, according to airport sources, was due to operational reasons.

According to Met department, the visibility is likely to reduce due to dense fog at the airport tonight and early tomorrow morning.

The airport has been witnessing thick fog for the past four days, leading to disruptions in the schedules of over 250 domestic and international flights.

Yesterday, about 26 flights were cancelled, 22 rescheduled and eight diverted to Mumbai, Jaipur and Ahmedabad after dense fog enveloped the airport for over eight hours.