Twenty-two Delhi-bound trains were delayed by up to six hours on Sunday due to weather-related conditions in the national capital, which recorded a minimum temperature of 8.2 degrees Celsius, one notch above the season's average.
According to the India Meteorological Department, humidity level recorded at 8.30 am was 79 per cent.
The IMD said there will be shallow to moderate fog in the coming week, with the possibility of a cloudy sky and light rains on January 9.
According to the railways, 22 Delhi-bound trains were delayed by one to six hours due to weather-related conditions in Delhi and different states.
The IMD has forecast a mainly clear sky on Sunday with shallow fog in the morning.
The Air Quality Index (AQI) was recorded at 341 'very poor' at 10 am, according to the Central Pollution Control Board (CPCB).
An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".