Delhi’s air quality in March and April was above standard limits

Read | Delhi News Highlights: Delhi AQI in March, April was above standard level; light rainfall expected today

The NCAP Tracker analysis noted: “With the extreme heat also came a power crisis that resulted in more coal burning, a primary source of pollution. On June 10, India’s power demand peaked at 211 GW against the peak requirement of 186 GW in 2021 and 75% of this was provided by coal-fired thermal power plants”.

“Extreme heat combined with stagnant air during a heatwave increases not only the amount of ozone pollution but also particulate pollution. The westerly winds from Balochistan, central Pakistan and Thar desert also carry dust adding to the PM10 levels. Locally, these prolonged dry spells during the summer months also mean more dust resuspension in the air,” it added.

This year, northwest India recorded the hottest March and April in 122 years. Maximum temperatures remained above normal in Delhi from the end of March onwards this year, recording an early, scorching start to the summer. The first heatwave spell that Delhi-NCR recorded this year began around March 27 and extended into April. Dry conditions contributed to the resuspension of dust – the city recorded no rainfall at all in March and there was a deficit of 98% rainfall in April.

The average PM10 level in March this year was 231.40 µg/m3, lower than 248.57 µg/m3 recorded last year, but higher than 184.71 µg/m3 recorded in March 2019. The PM10 concentration was higher in April (291.12 µg/m3) and May (246.51 µg/m3) this year when compared to March.

The NCAP Tracker uses data from the Central Pollution Control Board. The average PM10 and PM2.5 levels in the summer months this year have remained above the standard limits. According to the National Ambient Air Quality Standards, the annual standard for PM2.5 is 40 µg/m3, while the annual standard for PM10 is 60 µg/m3.

Nitrogen dioxide levels also remained high in March and April this year, standing at an average of 46.22 µg/m3 in March and 51.28 µg/m3 in April. This is above the annual average of 40 µg/m3 specified by the air quality standards.