Visibility was severely impacted in several areas of Delhi on Wednesday morning as dense fog engulfed the city in the early hours and minimum temperature was recorded at 7.8 degrees Celsius, a notch above the normal.

An orange alert was issued by the Met department across the city at 8 am as visibility in many parts remained around 50 metres.

Trains are running late and there could be flight delays and cancellations, according to an official.

According to IMD colour codes, ‘yellow’ alert calls for authorities to be aware, an ‘orange’ alert calls for them to remain prepared, while ‘red’ alert calls for most vigil and action.

As per the satellite images taken at 5.15 am, dense to very dense fog conditions prevailed across the national capital.

The visibility in Delhi's main weather station Safdarjung was recorded at 50 metres while in Palam it stood at 125 metres at 5.30 am.

About 25 trains scheduled for arrival at Delhi railway stations are running late due to fog.

However, the situation may improve after 11 am according to an official of private weather forecasting agency Skymet.

"Very dense fog engulfed Delhi NCR. Visibility is almost nil at many places. At 07:30 hours Palam has reported 50 metres visibility. Take care and drive carefully. Improvement expected after 11 am," Skymet official Mahesh Palawat said in a post on X.

"Flight delay and flight cancellation is possible. Dense fog to impact rail, road, air traffic today across Punjab, Haryana, Delhi, UP & north Rajasthan," he said in another post.

The AQI was recorded in the “very poor” category at 383, up from 374 recorded at 9.05 am on Tuesday.

An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.