Delhi’s air quality dips as winds keep mercury below normal
According to forecasts, consistent winds over the next few days will lead to a dip in temperature and negatively impact air quality.
Delhi’s air quality deteriorated to the “poor” category on Tuesday, despite cold northwesterly winds persisting that kept the temperatures below normal levels for this time of the year.
The Capital recorded an air quality index (AQI) reading of 234 (“poor”) over the past 24 hours, according to the Central Pollution Control Board’s (CPCB’s) daily bulletin—a fall from a reading of 186 (“moderate”) recorded a day before.
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According to forecasts, consistent winds over the next few days will lead to a dip in temperature and negatively impact air quality, keeping it in the “poor” category.
“Delhi’s air quality is likely to be in the ‘poor’ category from December 11 till December 13. The AQI in the subsequent six days should also be in ‘poor’,” said the Centre’s Early Warning System for Delhi on Tuesday.
Delhi’s minimum temperature was 8°C on Tuesday, which was two degrees below normal and slightly down from 8.2°C recorded a day earlier.
The minimum is forecast to dip further and touch 7°C by Wednesday and 6°C by Thursday, the India Meteorological Department (IMD) said.
Delhi’s maximum temperature, meanwhile, was 23°C, two degrees below normal but up from the season-low of 21.6°C recorded a day before.
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“The maximum should remain below normal, hovering around 23°C, over the next three days,” an IMD official said.
“Even with sunshine, cold northwesterly winds are providing a wind chill factor, which is leading to a drop in both maximum and minimum temperatures. We can expect a further drop of 1-2°C over the next three days as winds remain consistent,” said Mahesh Palawat, vice president at Skymet.
Palawat said that although wind speed touched 17km/hr on Tuesday, winds dipped marginally on Monday evening and night-time, leading to the marginal deterioration in air quality.
“It is unlikely to deteriorate further as winds of 10-15 km/hr are expected over the next three days,” he added.
The day’s average AQI was calculated on the basis of data from 38 ambient air quality monitoring stations, with only one station, at RK Puram, recording a “very poor” AQI of 335 at 4 pm.
Twenty-seven stations were in the “poor” category, with an AQI between 200 and 300, while the rest were in the “moderate” category, with AQIs ranging between 100 and 200.
This December, Delhi has only recorded one “very poor” air day, on December 8 (302), with the AQI remaining below 300 on all other days.
This has been an unusually clean start to December, with four “moderate” air days already recorded, which is the highest number of such days in December since AQI data was launched in 2015.
Delhi recorded “moderate” AQI on December 4 (178), December 5 (165), December 6 (197) and December 9 (186).
Delhi has never recorded a “good” or “satisfactory” air day in December since 2015, making this a good start to December, as reported by HT a day before.
In December, the AQI recorded by Delhi was 140, on December 26, 2015. Besides, three “moderate” air days each were recorded in December 2022, 2019 and 2015.
