Delhi’s Air Quality Declines to ‘Poor’ Category Amid Cold Winds

Delhi’s air quality worsened to the “poor” category on Tuesday, despite the ongoing cold northwesterly winds that kept temperatures below normal for this time of year. On Tuesday, the city’s minimum temperature was 8°C, two degrees lower than usual, slightly down from the previous day’s 8.2°C. The air quality index (AQI) reached 234 (“poor”), up from 186 (“moderate”) the day before, according to the Central Pollution Control Board’s daily report.

Forecasts predict that consistent winds will continue over the next few days, causing temperatures to drop further and worsening air quality, keeping it in the “poor” category. The Centre’s Early Warning System for Delhi stated that the AQI is expected to remain in the “poor” category from December 11 to 13. It may continue at this level for the following six days.

The minimum temperature is forecast to decrease further, reaching 7°C by Wednesday and 6°C by Thursday, according to the India Meteorological Department (IMD). Meanwhile, the maximum temperature was 23°C, two degrees below normal, but slightly higher than the season’s lowest of 21.6°C recorded the previous day.

The IMD predicts the maximum temperature will stay below normal, hovering around 23°C over the next three days. Despite sunshine, the cold winds are contributing to a wind chill effect, causing both maximum and minimum temperatures to fall. Winds are expected to remain consistent at 10-15 km/hr over the next few days, with a slight drop in wind speed observed on Monday evening, which led to a slight deterioration in air quality.

The AQI for the day was based on data from 38 air quality monitoring stations. One station, at RK Puram, recorded a “very poor” AQI of 335 at 4 pm. Twenty-seven stations showed a “poor” AQI, with readings between 200 and 300, while the rest were in the “moderate” category, with AQIs ranging between 100 and 200.

So far this December, Delhi has recorded only one “very poor” air day on December 8 (AQI 302), with the AQI staying below 300 on other days. This December has seen an unusually clean start, with four “moderate” air days, the highest number of such days in December since AQI data was first tracked in 2015.

In comparison, Delhi has never experienced a “good” or “satisfactory” air day in December since 2015, making this relatively clean start noteworthy. The highest AQI recorded in December was 140, on December 26, 2015, with other years such as 2022, 2019, and 2015 each seeing only three “moderate” air days.