22 Trains Delayed, 5 Flights Diverted as Dense Fog Envelops Delhi; Mercury Settles at 7 Degrees

New Delhi: Delhi and its surrounding national capital region woke up to a densely foggy morning on Wednesday with the minimum temperature settling at 7 degree celsius accompanied by cold winds.

At least 22 Delhi-bound trains were delayed due to low visibility and a thick layer of fog in the Northern Railway region. On Tuesday, as many as 25 North India-bound trains were delayed by over 5 hours.

Meanwhile, five flights were diverted as the Captain was not trained to land under CAT3 conditions, which are activated when the visibility of air drops, at the Delhi airport.

"Five flights diverted as captain was not trained to land under CAT conditions," the official said.

When the runway visual range (RVR) is minimum 200 metres, then only that pilot — who is trained in instrument landing system Category 3A (CATIIIA) — can land the aircraft.

If the RVR is minimum 50 metres, then a pilot who is trained in using CATIIIB landing system can land the aircraft at the airport.

Weather experts said wind direction will change and cold northwesterly winds will start blowing in from the hills on Wednesday, which will lead to a dip in the temperatures.

Dense to very dense fog was observed over Punjab, north Rajasthan, Haryana and Delhi, East UP and Bihar at 5:30 am on Wednesday, said the Indian Meteorological Department. "Visibility recorded Patiala, Bikaner, Churu, Hissar, Delhi, Baharaich, Gorakhpur and Patna — 25 each; Lucknow-50," the Met department said.

The mercury is likely to drop to 6 degrees Celsius in the next two to three days as temperatures are expected to dip with the commencement of icy winds from the hills on Wednesday.

A fresh western disturbance January 28 onwards is expected to trigger "fairly widespread" rainfall in the entire northwest India and "good" snowfall in the hills, the weatherman said.

On Tuesday, calm winds and cloud cover led to an increase in pollution levels and the temperature was recorded at 9.2 degrees Celsius, which was two notches more than normal.

The overall air quality index has been between 364 to 269, so far, this week.