A train waits at Patna station, engulfed in fog early on Sunday.

Dense fog blanketed parts of the north and east of the country, throwing road, rail and air traffic haywire and leaving travellers stranded. Twenty-two people were killed in road accidents as a result of the fog.

In East Champaran, Bihar, 18 people were killed when the bus carrying them plunged into a ditch. Four persons were killed and 12 hurt in two other accidents in Mainpuri, Uttar Pradesh.

In Delhi, some flights were delayed by about two hours as visibility dropped to 300 m at Indira Gandhi International Airport.

Trains also ran behind schedule. The New Delhi-Bhubaneswar Rajdhani was running indefinitely late, a railway spokesperson said in Bhubaneswar.

The met office has said the fog could persist for some days. (AFP picture, PTI text)