About 21 international, 3 domestic flights were delayed causing inconvenience to score of travellers.
The rail traffic has also been disrupted with 13 trains being delayed.
"Delhi will witness fog on Monday. Fog will remain till the forenoon and the sky will be mainly clear during the day," an official of the India Meteorological Department (IMD) was quted by news agency as saying.
The official further said, "The minimum temperature is expected to be around 7 degrees Celsius while the maximum is expected to hover around 17 degrees Celsius."
"On Sunday, visibility till 9 am was less than 50 meters. The condition improved later in the day," the official added.