More than 20 Delhi-bound trains were delayed and one cancelled due to dense fog on Sunday morning.
The northern railways said two trains were also rescheduled as the visibility reduced to less than 150 metres in Delhi.
According to the Delhi airport, eight domestic and two international flights were delayed at the Indira Gandhi International Airport.
The minimum temperature in the city settled at 10.6 degrees Celsius.
The weather department has predicted cloudy skies for the day and the maximum temperature is excepted to hover around 22 degree Celsius.