Delhi snaps 32-day streak as AQI improves to ‘poor’ zone

Consistent winds over a 24-hour period, coupled with three straight days of bright sunshine, helped improve Delhi’s pollution levels on Sunday, as the Capital’s air quality dropped into the “poor” zone — snapping a streak of 32 days during which the air quality index (AQI) reading was 301 or higher.
The Central Pollution Control Board (CPCB), in its daily bulletin released at 4 pm, stated that Delhi’s 24-hour average AQI was 285 (poor) — a sharp drop from an AQI of 346 (very poor) on Saturday.
The last time Delhi had an AQI below 301 was on October 29, when the reading was 268.

“Since Saturday, Delhi was recording consistent dry northwesterly winds with wind speeds of around 8 kmph. Winds did not become calm overnight and on Sunday, picked up to speeds of 15 kmph during the day, which helped in dispersion of pollutants. We also don’t have dense fog in the region, so we are seeing adequate sunshine during the day, which again helps in pollutants and gases dispersing as the mixing height is fairly high,” said Mahesh Palawat, vice president at Skymet meteorology.
Sunday’s average AQI at 4 pm was based on readings from 38 of the 40 ambient air quality monitoring stations in Delhi. None of the 38 stations were in the “severe” zone — the highest reading was 330 at Mundka.
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The continuous winds also meant that the city’s average AQI continued to improve as night fell, dipping to 283 at 10 pm.
However, forecasts show that the AQI is likely to return to the “very poor” zone on Monday and Tuesday as wind speeds dip, before dropping back to the “poor” range on Wednesday.
This November, Delhi was plagued by high pollution levels, with an average 24-hour AQI of 374 — the second highest for the month after 2021, when it was 376.
During this period, the Capital eight “severe” days in a 10-day window, with the city recording an AQI of 494 on November 18 — the joint second highest for Delhi.
Meanwhile, Delhi recorded a slight uptick in temperature, as the minimum rose to 11.4 degrees Celsius (°C) — a notch above normal — after two straight days of a minimum below 10°C.
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The reading was at the Safdarjung observatory, which is the representative weather station for Delhi. However, India Meteorological Department (IMD) data revealed that other parts of the city were slightly colder, with the weather stations at both Aya Nagar and Lodhi Road was 10.2°C.
The Capital’s maximum also rose slightly to 27°C — up from 26.8°C a day earlier, and a degree above the normal. However, the lowest maximum was 23.9°C at Palam.
Palawat said a western disturbance influenced parts of northwest India and resulted in snowfall in the upper reaches of the Himalayas over the weekend, and will likely lead to a dip in the mercury from Tuesday.
Delhi ended November with an average monthly maximum temperature of 29.7°C — the highest for November in at least 13 years, IMD data available from 2011 showed. The average monthly minimum was 14.7°C, the highest since 2019, when it was 15°C.
IMD also said that shallow fog was reported in the National Capital Region, with minimum visibility recorded at around 500 metres on Sunday morning. Forecasts show that shallow to moderate fog is likely to persist, with winds picking up to 20 kmph by December 4. The minimum should hover around 11°C during this period, while the maximum will be around 26°C, IMD said.