New Delhi: Flight operations at New Delhi's Indira Gandhi International (IGI) Airport resumed on Tuesday after being disrupted for nearly two hours in the morning due to poor visibility owing to the dense and thick fog. Departure of all flights were on hold as the minimum visibility required for take off is 125 metres.

Three international and one domestic flights were diverted due to poor visibility. However, arrivals were not affected, an official said.

According to the official, since the Low Visibility Take Off (LVTO) requirement was not being fulfilled, departure of flights were on hold for two hours from around 7:15 am. Departure of flights resumed at 9:16 am.

The Indira Gandhi International Airport is the busiest in the country and on an average sees more than 70 flight movements per hour. This includes both arrivals and departures.

Private weather service Skymet had predicted a foggy morning on Christmas. "While the day will remain sunny, haziness will prevail in the sky. Minimum temperature may see a slight increase but will continue to be below normal levels," it said.

Apart from air traffic getting affected, train and road movements are also severely impacted each year due to fog. Road accidents are also frequent. On Monday morning, eight people died in a 50-vehicle pileup near Haryana's Jhajjar.

Meanwhile, the air quality index of Delhi continues to remain in ‘severe’ category. At 8 am on Tuesday, AQI at Anand Vihar was 431.