Visibility in Amritsar city and other parts of the district was reduced to 50 metres, Met officials said.
In Ludhiana, the fog situation was a little better with visibility of 750 metres.
In neighboiuring Haryana, Hisar town witnessed fog, with visibility being reduced to 150 metres.
However, Chandigarh, Karnal, Patiala and Ambala saw sunshine on Monday morning with some haze.
The maximum temperatures had dipped at most places on Sunday following rainfall on Christmas Day.
Chandigarh received 8.9 mm rain in the city while the airport area received 17 mm rain.
The city also saw a maximum temperature of 17.4 degrees, four degrees below normal.
In Haryana, the maximum temperature hovered between 15 to 19 degrees.
Met department officials have predicted dense fog in the region during morning hours in coming days.