Poor visibility, owing to 'svere' air quality and fog, led to delay in departure of 13 trains from th national capital on Saturday.
According to the MeT Department, the city recorded a minimum of 5.4 degrees Celsius, a notch below the season's average.
The weatherman forecast moderate fog in the next 24 hours and mild rainfall. In Palam and Safdarjung, the visibility was zero and 400 metres respectively at 5.30 am, and 50 and 400 metres at 8.30 am.
According to a Railways spokesperson, 13 trains were delayed due to fog and the average delay time was two to three hours.
Farakkha Express Malda-Delhi Junction, Mahabodhi Gaya-New Delhi, Poorva Express Howrah-New Delhi and Garib Rath Jaynagar-Anand Vihar were some of the trains running behind schedule.
However, operations at the Delhi airport remained unaffected. The visibility has been good enough at the Delhi airport and normal operations have been going on, an official said.
The maximum temperature in the evening is likely to hover around 20 degrees Celsius. On Friday, the maximum temperature was recorded at 18.4 degrees Celsius while the minimum temperature was recorded at 7.1 degrees Celsius.
Meanwhile, Delhi's air quality deteriorated again to severe category on Saturday due to unfavourable meteorological conditions after showing a slight improvement on Friday, authorities said.
According to the Central Pollution Control Board (CPCB) data, the overall Air Quality Index (AQI) in the city reached 417, which is in the 'severe' category.
Twenty six areas in Delhi recorded 'severe' air quality, while 8 gauged 'very poor', it said.
In NCR areas, Ghaziabad, Faridabad, Gurgaon and Noida recorded 'severe' air quality, the CPCB said.
Delhi's air quality slightly improved on Friday with improved wind speed but due to unfavourable meteorological conditions again turned severe, officials said.
The overall PM2.5 level (fine particulate matter in the air with a diameter of less than 2.5 micrometers) in Delhi was recorded at 298 while the PM10 level was at 468, the CPCB said.
An AQI between 100 and 200 comes under 'moderate' category, 201 and 300 is considered 'poor', 301 and 400 'very poor', while that between 401 and 500 is 'severe'.
Authorities said the severe air quality is due to unfavourable meteorological conditions and sufficient rainfall that is predicted for Saturday might improve the air quality but warned that little showers with calm winds would only aggravate the situation rapidly.
As per the Centre-run System of Air Quality and Weather Forecasting (SAFAR) model, fog intensity is likely to decline with increased gusty winds.
"An active western disturbance is very likely to cause fairly widespread moisture intrusion over the northern region, including Delhi, but only after three days when withdrawal is expected," it said.
In view of the air quality in Delhi, the Supreme Court-appointed Environment Pollution Control Authority (EPCA) had ordered a 24-hour ban on the entry of trucks into the national capital.
The entry of trucks to Delhi would be disallowed "from 11 pm on Friday to 11 pm on Saturday in view of the severe pollution in the city, the EPCA instructed authorities.
In a letter to the chief secretaries of Delhi and the neighbouring states of Uttar Pradesh and Haryana, EPCA chief Bhure Lal directed them to stop the entry of truck traffic into the national capital (except essential commodities) during the period.
This would be a second time this season that a ban on the entry of trucks would be imposed.
Earlier, it was done in November when the deterioration of air quality was observed.
(With inputs from agencies)