Delhi recorded its lowest minimum temperature of the season at 3.6 degrees Celsius on Saturday and thick fog blanketed several parts of the city, the India Meteorological Department (IMD) said.
On Friday, the national capital had recorded a minimum temperature of 3.9 degrees Celsius.
The maximum temperature on Saturday settled at 18.1 degrees Celsius, two notches below the season's average, and the minimum was recorded at 3.6 degrees Celsius, four notches below the season's average, the IMD said.
The visibility at Safdarjung Observatory, Delhi's main weather station, was 200 metres at 5:30 am, it said.
According to the railways, 18 Delhi-bound trains were delayed by one to six hours due to the fog.
According to the IMD, very dense fog is when visibility is between 0 and 50 metres, between 51 and 200 metres is dense, between 201 and 500 metres moderate, and between 501 and 1,000 metres shallow.
The 24 hour Delhi's Air Quality Index (AQI) stood at 399 at 4 pm which comes under 'very poor' category, according to Central Pollution Control Board (CPCB) data.
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'.
The humidity oscillated between 91 per cent and 79 per cent, it said.
The weather department has predicted cold wave on Sunday. The maximum and minimum temperatures are likely to settle around 19 and 4 degree Celsius respectively, it added.
