Delhi’s air quality deteriorated on Monday but remained in the very poor category as calm winds continued to negatively impact the dispersion of pollutants. A 24-hour average air quality index (AQI) of 337 (very poor) was recorded at 10am, compared to 325 (very poor) on Sunday.
The AQI was unlikely to touch the severe category and remain in the very poor range until November 2. The air quality was likely to be between the very poor and poor categories for the subsequent six days.
An AQI between zero and 50 is considered good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor, and 401 and 500 severe.
The AQI touched the very poor category again on Saturday following a change in wind direction from northwesterly to southeasterly. The change reduced the impact of stubble burning but also led to a drop in local wind speed.
The wind direction changed to southeasterly from Saturday and winds were also slow even during the day. “We expect wind direction to remain southeasterly until November 1,” said India Meteorological Department scientist Kuldeep Srivastava.
A minimum temperature of 16.2°C, which is normal for this time of the year, was recorded on Monday compared to 16.3°C on Sunday. It dropped to 14.3°C on Saturday.