Delhi’s air quality improves marginally, enters ‘poor’ zone

According to the Central Pollution Control Board, the hourly Air Quality Index (AQI) at 7am was 288. On Tuesday, the average 24-hour AQI was 305 - in the lower end of the “very poor” category

NEW DELHI: Delhi’s air quality improved marginally and entered the “poor” zone on Wednesday morning amid shallow fog as overcast weather was expected in the Capital.

A metro train runs amid low visibility due to fog on a cold morning in New Delhi recently. (PTI)

According to the Central Pollution Control Board, the hourly Air Quality Index (AQI) at 7am was 288. On Tuesday, the average 24-hour AQI was 305 - in the lower end of the “very poor” category. PM 2.5 was the dominant pollutant in the air.

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 air quality was expected to improve. On Tuesday, the System of Air Quality and Weather Forecasting And Research said the AQI improved to the “poor” category due to an increase in mixing layer height to 1.5km on Monday that ventilated the near-surface pollutants. Light rain due to western disturbance was likely to improve the AQI further to the upper end of the “moderate” or lower end of the “poor” category. “On 30th (December), 31st (December), and 1st (January), winds are likely to be low reducing ventilation of pollutants, and AQI is expected to be within the ‘poor’ category. From 2nd (January) onwards improvement in AQI is likely due to relatively high winds.”