Delhi’s air quality remains ‘poor’; minimum temperature recorded at 15.7°C

Delhi’s air quality remains ‘poor’; minimum temperature recorded at 15.7°CThe count is lower than the 1,048 fires detected over the corresponding period last year. (HT photo)Delhi’s air quality index (AQI) remained in the ‘poor’ category as the city recorded a minimum temperature of 15.7°C on Wednesday, 0.4 degrees below normal.The development comes a day after the national Capital recorded its coldest day of the month, clocking a minimum temperature of 15.3°C.Delhi’s AQI was recorded at 230 at 8am. Two monitoring stations, Jahangirpuri and Vivek Vihar, recorded ‘very poor’ air quality with readings of 307 and 320 respectively. Sixteen stations were in the moderate category.The 24-hour AQI at 4pm on Tuesday was 197 but by evening it plummeted to poor.Also Read: Mercury drops to 15.3°C as Delhi records coldest day of the month; rain likely in next 2 daysParticulate matter 2.5 (PM2.5) was the predominant pollutant at 42 of Delhi’s 58 reporting stations at 6am on Wednesday, while PM10 was the main pollutant at 15 stations, according to Central Pollution Control Board (CPCB) data.Farm fires dataMeanwhile, satellite data from National Aeronautics and Space Administration (NASA) detected 767 farm fires in Punjab and Haryana between October 1 and 27, including 661 in Punjab and 106 in Haryana. Of these, 65 fires were detected on Tuesday.The count is lower than the 1,048 fires detected over the corresponding period last year.However, the figures could be underreported, as the timing of stubble burning has been shifting later each year and satellite observations capture only a portion of the fires.Also Read:Farm fires cross last year’s tally, Punjab’s Tarn Taran accounts for half of 454 casesAccording to the data, 98% of the fire heat recorded by the Meteosat satellite in 2025 occurred after 3pm, compared with 94% in 2024. Much of the burning now takes place after the satellite passes over the region at around 1:30pm, meaning both years’ counts are likely to underestimate the actual number of fires.NASA’s satellite count of farm fires in Punjab and Haryana is now a large undercount. NASA counted 4,824 fires in the two states between October 1 and November 30, 2025, 94% fewer than over the same period in 2021, while the area burned fell only 19%, according to iFOREST, a research group that maps it from before-and-after satellite images. Most of the burning now happens after NASA’s satellite passes over the region at about 1.30pm.An HT analysis of data from Meteosat, a European weather satellite that scans the region every 15 minutes, shows the shift. In 2021, about 40% of the fire heat Meteosat recorded came between 1pm and 3pm. In 2025, less than 1% did, and 98% came after 3pm. India’s INSAT-3DS satellite, which scans every half hour, shows the same: from October 16, 2025, 99% of the fire pixels it flagged in Punjab and Haryana came after 3pm.Cold morning in the cityAyanagar was the coldest among the city’s five weather stations, recording a minimum temperature of 14.8°C, followed by Palam at 15.5 degrees Celsius and Safdarjung at 15.7°C. Lodhi Road recorded a minimum of 16.2°C, while the Ridge station recorded 16.5°C, according to India Meteorological Department (IMD) data.The maximum temperature at Safdarjung on Tuesday was 31.5°C, 0.3 degrees below normal. Palam recorded a maximum of 29.9°C, while Lodhi Road, the Ridge and Ayanagar recorded 31.2°C, 31 degrees Celsius and 30.8°C, respectively.