Delhi’s air quality stayed in the "very poor" category for the sixth consecutive day on Friday, while the city experienced its coldest night of the season with the temperature dropping to 9.5 degrees Celsius.

The nighttime temperature dipped a notch below normal on Friday, making it the lowest of the season so far, according to the India Meteorological Department (IMD).

The second coldest night of the season was recorded on Thursday when the temperature settled at 10.1 degrees Celsius, while November 21 was the third coldest night at 10.2 degrees Celsius.

Meanwhile, Delhi’s 24-hour average Air Quality Index (AQI) was recorded at 331 at 4 pm, a slight increase from 325 recorded on Thursday, according to Central Pollution Control Board (CPCB) data.

Out of the 37 monitoring stations in the national capital, two recorded air quality in the "severe" category on Friday -- Bawana (416) and Mundka (402).

None of the stations had been in the "severe" category in the last three days.

Of the remaining stations, 26 recorded "very poor" air quality, while nine reported "poor" air quality, according to the Sameer app.

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 AQI previously peaked at 419 on November 20, followed by readings of 371 on November 21, 393 on November 22, 412 on November 23, and 318 on November 24.

Meanwhile, PM2.5 remained the primary pollutant in Delhi, with levels recorded at 143 µg/m³ at 4 pm on Friday. These fine particles pose significant health risks as they can penetrate deep into the lungs and enter the bloodstream.

According to the Centre’s Decision Support System (DSS) for Air Quality Management, vehicular emissions contributed 21.6 per cent to Delhi’s pollution on Friday.

While stubble burning accounted for 5.8 per cent of the pollution on Tuesday, no data was provided for it on Wednesday or Thursday.

On Friday, Punjab reported 32 incidents of stubble burning, Haryana reported nine, while Uttar Pradesh reported 215.

Between September 15 and November 29, Punjab reported 10,887 farm fire incidents, Haryana 1,389, and Uttar Pradesh 5,769, according to satellite data.

The Air Quality Early Warning System for Delhi predicted smog and mist on Friday evening and night, with mainly clear sky on Saturday.

Shallow to moderate fog is likely on Saturday morning. The predominant surface wind is expected to come from variable directions at speeds less than 4 kmph on Saturday morning, gradually increasing to 6-8 kmph from the northwest during the afternoon, before reducing again in the evening and night.

Meanhwhile, Delhi’s maximum daytime temperature on Friday was recorded at 26.4 degrees Celsius, 0.4 degrees above normal, making it the second-lowest maximum of the season.

The coldest daytime temperature was recorded on November 19 at 23.5 degrees Celsius.

Humidity levels fluctuated between 99 per cent and 64 per cent during the day on Friday.

The weather department has forecast shallow fog for Saturday, with maximum and minimum temperatures expected to hover around 26 degrees Celsius and 10 degrees Celsius, respectively.