A layer of dense fog enveloped the national capital on Wednesday morning hampering flight and train operations, officials said.

The city is likely to receive light rain during the day, according to the India Meteorological Department (IMD).

Zero visibility was reported at the Indira Gandhi Airport at 6.30 am as a thick layer of fog engulfed the area. The visibility remained the same till 9 am, they said.

The Delhi airport saw diversions of at least three flights on Wednesday morning due to bad weather, an official said.

Due to the "very dense" fog, several trains were running late, another official said.

According to the IMD, light rain or thundershower accompanied by gusty winds with a speed of up to 30-40 kmph is likely towards the evening or night.

Weather fluctuations are expected to continue till February 3 because of a western disturbance, with further changes anticipated from thereon, a senior official said

Delhi recorded a minimum temperature of 7.3 degrees Celsius, a notch below the season's average, on Wednesday.

The average maximum temperature in Delhi this month till January 30 stood at 17.7 degrees Celsius, the lowest in 13 years, according to official data till Tuesday.

The average minimum temperature in the national capital during the same period was pegged at 6.2 degrees Celsius, the second lowest in 13 years, the data showed.

Meanwhile, the Air Quality Index (AQI) was recorded in the 'very poor' category with a reading of 370 at 8 am.

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'.