Delhi Records Season's Coldest Night, Air Quality Remains 'Very Poor'

Delhi's air quality remained in the "very poor" category for the fifth consecutive day on Thursday, while the city recorded its coldest night of the season.

The minimum temperature dipped to 10.1 degrees Celsius on Thursday, normal for this time of the year, according to the India Meteorological Department (IMD).

The second coldest night of the season was recorded on November 21, with the temperature settling at 10.2 degrees Celsius, while the third coldest night was on Wednesday, November 27, when the nighttime temperature dropped to 10.4 degrees Celsius.

Meanwhile, Delhi's 24-hour average Air Quality Index (AQI) was recorded at 325 at 4 pm, a slight increase from 303 recorded on Wednesday, according to data from the Central Pollution Control Board (CPCB).

None of the 39 monitoring stations in the capital recorded air quality in the "severe" category, continuing the trend observed on Tuesday and Wednesday.

The AQI had peaked at 419 on November 20, followed by readings of 371 on November 21, 393 on November 22 (Friday), 412 on November 23 (Saturday) and 318 on November 24 (Sunday).

An AQI between 301 and 400 is classified as "very poor", while levels above 400 are considered "severe". An AQI between 0 and 50 is considered "good", 51-100 "satisfactory", 101-200 "moderate", 201-300 "poor", 301-400 "very poor", 401-450 "severe" and above 450 "severe plus".

The primary pollutants remained PM2.5 and PM10.

These fine particles, particularly PM2.5, pose significant health risks as they can penetrate deep into the lungs and enter the bloodstream.

The Centre's Decision Support System (DSS) for Air Quality Management estimated that 21.6 per cent of Delhi's pollution on Thursday was contributed by vehicular emissions.

Stubble burning contributed 5.8 per cent of the pollution on Tuesday. But no data was provided for Wednesday.

The DSS provides daily estimates for vehicular emissions, while stubble-burning data is typically available the following day.

On Thursday, Punjab reported 34 incidents of stubble burning, Haryana reported seven and Uttar Pradesh reported 103.

Between September 15 and November 28, Punjab recorded 10,855 farm fire incidents, Haryana 1,380 and Uttar Pradesh 5,554, according to satellite data.

The predominant surface wind was from variable directions with a speed of less than 6 kmph until the evening, decreasing further to less than 4 kmph from the north, according to the Air Quality Early Warning System for Delhi.

Smog or shallow fog is likely during the evening and night on Thursday. The system predicted that on Friday, the predominant surface wind would be from variable directions with a speed of less than 4 kmph during the morning, it said.

Moderate to dense fog is likely in the morning. The wind speed is expected to increase later in the afternoon to less than 6 kmph from variable directions and decrease again to less than 4 kmph in the evening and night. Smog or shallow fog is expected during the evening and night, with a mainly clear sky forecast for Friday.

Meanwhile, the city's maximum daytime temperature was recorded at 27 degrees Celsius, a notch above normal, making it the second lowest of the season so far, according to the IMD.

The coldest daytime temperature was recorded on November 19 at 23.5 degrees Celsius, followed by 27 degrees Celsius on Thursday and 27.2 degrees Celsius, the third lowest, on both November 18 and November 23, according to IMD data.

Humidity levels fluctuated between 97 per cent and 53 per cent during the day. The weather department has forecast moderate weather conditions for Friday, with the maximum and minimum temperatures expected to hover around 26 degrees Celsius and 10 degrees Celsius respectively.

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