Five flights were diverted from Indira Gandhi International Airport in New Delhi on Wednesday as dense fog engulfed the national Capital, PTI reported. “Five flights diverted as captain was not trained to land under CAT conditions,” an airport official said.

When the runway visual range is 200 metres, only pilots who are trained to land under Category 3A (CATIIIA) conditions can do so. When the range is 50 metres, only pilots trained under Category 3B can land.

Dense fog enveloped the national Capital on Wednesday morning, with the minimum temperature settling at 7.1 degrees Celsius, according to the India Meteorological Department. The fog led to 22 Delhi-bound trains getting delayed, News18 reported. On Tuesday, as many as 25 North India-bound trains had been delayed by over five hours.

Dense to very dense fog was observed over Punjab, North Rajasthan, Haryana and Delhi, Eastern Uttar Pradesh and Bihar at 5.30 am on Wednesday, the weather department said in a tweet. It added that in Patiala, Bikaner, Churu, Hissar, Delhi, Baharaich, Gorakhpur and Patna, the visibility was as low as 25 metres, while in Lucknow it was 50 metres. The department added that dense to very dense fog will continue in Delhi till 10 am or 11 am on Wednesday, after which conditions will improve.

The weather department said that a fresh western disturbance from January 28 is expected to trigger fairly widespread rainfall in Northwest India and good snowfall in the hills, News18 reported. On Tuesday, the minimum temperature in Delhi had settled at 9.1 degrees Celsius, one degree above normal, due to calm winds and cloud cover.

At 8 am on Wednesday, the Air Quality Index in New Delhi was 376, in the “very poor” category, according to the Central Pollution Control Board.