Four persons, including a woman and child, were killed on Monday morning when a car collided with a bus due to thick fog in Punjab's Tarn Taran district, police said.

Three people were injured in the accident. There were seven passengers in the car.

The accident took place near Harkie Patan, 185 km from here, on the highway connecting Amritsar with Moga town.

Police officials said that the impact of the collision was such that it took nearly two hours for police and local authorities to recover those from inside the vehicle.

Met officials here said that thick fog had engulfed several parts of Punjab and Haryana on Monday after a gap of few days.

Visibility in Amritsar, Ludhiana and Patiala in Punjab and Karnal and Ambala districts in Haryana was reduced to less than 50 metres.

Road and rail traffic were hampered in both states.

Arrival and departure of at least 10 flights to and from the Guru Ram Das Jee International Airport at Amritsar was delayed. 

The morning temperature at most places was between 11 and 14 degrees Celsius on Monday after a relatively warm Sunday.

On Sunday, the minimum temperature at most places in Punjab, Haryana and Chandigarh was six to 10 degrees above normal.

Chandigarh and its surrounding areas received some rain on Sunday. However, there was bright sunshine in Chandigarh on Monday.