As many as 24 domestic and international flights were delayed as early morning fog hit Delhi and nearby areas.
With visibility dropping to less than 50 metres, the dense fog also hit rail and road traffic.
"Most of the north-bound trains were several hours late due to dense fog in the northern zone. While 55 trains have been delayed, 13 trains had to be cancelled," a Northern Railways official said.
Tuesday's minimum temperature settled four notches below the season's average at 4 degrees Celsius. Visibility dropped to less than 50 metres at 8.30am from relatively better conditions at 5.30am when it was recorded at 400 metres.
Predicting a clear day ahead, Met Department officials said the skies will turn partly cloudy midnight onwards.
"The skies will become partly cloudy from midnight accompanied by moderate to dense fog. The maximum temperature will hover around 16 degrees Celsius," an official said.
Monday's maximum temperature was 16.2 degrees Celsius, five notches below the season's average while the minimum settled at 5.7 degrees Celsius, two notches below the season's average.