As many as 45 Delhi-bound trains were cancelled and 30 delayed after dense fog engulfed the national capital early on Tuesday, a railway official said.
Seven trains was rescheduled.
Flight operations, however, remained unaffected.
The national capital woke up to chilly Tuesday morning, with the minimum temperature settling at 6.8 degrees Celsius, a couple of notches below the season's average, the Met Office said.
According to weather office, the day ahead is likely to be partly cloudy.
"The day will be partly cloudy throughout. Moderate to dense fog can be seen in many places till forenoon," an official of the India Meteorological Department (IMD) said.
The maximum temperature is likely to hover around 19 degrees Celsius. Humidity at 8.30 a.m. was recorded at 100 percent. Visibility stood at 200 meters.
Monday's maximum temperature was recorded at 18.7 degrees Celsius, three notches below the season's average, while the minimum temperature settled at 6.4 degrees Celsius, a notch below average of this time of the season.