Road and railway traffic was affected due to low visibility, which reduced to less than 100 metres at some places. Traffic on highways was plying slow, the police said.
The Amritsar-Ambala-Delhi stretch of the National Highway No. 1 (NH-1) was worst affected due to dense fog at several places.
The foggy weather continued over the region with maximum temperatures ranging from nine to 11 degrees below normal.
On the Tuesday morning minimum temperature in Chandigarh was 9 degrees Celsius, three degrees below average.
Narnaul in Haryana was the coldest region in the north Indian plains with the morning minimum temperature at 1.2 degrees Celsius lower than Shimla in Himachal Pradesh that recorded 2.2 degrees Celsius.
In Punjab, Amritsar was the coldest at five degrees Celsius.
Trains coming to Chandigarh were delayed by several hours and passengers had to wait in the cold at the railway station.
Motorists had a tough time driving to work due to dense fog.
The Education Department in Punjab has changed the timings of government aided and private schools in the state owing to the inclement weather and foggy conditions.
The changed timings would come into force from December 24 and will be in force till January 15.
An official said the timings of the primary schools would be from 10 a.m. to 3 p.m. and the middle, high and senior secondary schools would be from 10 a.m. to 4 p.m.
( With inputs from IANS )