Poor visibility due to the dense fog disrupted train services in northern India on Sunday, causing inconvenience to thousands of commuters.

Northern Railways rescheduled more than three dozen trains from and to Delhi. A number of trains reached the national capital 12-22 hours late.

Lucknow-Delhi Swarn Shatabdi Express reached the national capital late by more than six hours at Charbagh station as dense fog force the operators to hold up the train at Kanpur and other stations during the course. The worst affected route was the busy Delhi-Howrah course.

Trains from the national capital to other parts of the country were also late. Ashwini Srivastava, senior DCM, Lucknow, Northern Railways, said, "All the trains coming from Delhi are late."

Trains from Punjab, Utter Pradesh, Bihar and West Bengal were also running late by many hours due to poor visibility, giving commuters a tough time waiting for trains.

Meteorologists expect the dense fog to continue in morning for at least the next 48 hours. They say day temperatures will drop further while early mornings will become chillier as well as foggier. However, clear sun is expected during the daytime.