The national capital on Friday recorded its lowest temperature this winter with the minimum dipping to 3.9 degrees Celsius, three notches below the season's average, the weather department said.

The India Meteorological Department (IMD) said it is the lowest minimum temperature in the last five years.

Dense fog also blanketed many parts of the city with the Palam Observatory reporting zero visibility at 5:30 am, the IMD said.

According to the Indian Railways, 23 Delhi-bound trains were delayed by one to six hours due to fog.

According to data by the Central Pollution Control Board (CPCB), the overall Air Quality Index (AQI) at 9 am stood at 348.

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 relative humidity at 8.30 am was 100 per cent, the IMD bulletin said.

The maximum temperature is likely to settle around 17 degrees Celsius.

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