Statsguru: Monsoon boosts Delhi's air quality, pollution challenges remain

Air quality in Delhi has improved significantly this monsoon but the national capital’s air woes are far from over.

The average air quality index in Delhi last month (data till 23rd August) was 70, the best since the pandemic, mainly because of abundant rains.

Some regions in the northwest and eastern belts of India have had scant or deficient rainfall this season. But Delhi, which is one of the 13 regions to witness excess rainfall since the beginning of June, has received over 525 mm rainfall or about 22 per cent more than its normal for this period. The country meanwhile, received 734 mm of rainfall which is over 7 per cent of the normal (chart 1).

But before this, the city had about 160 days of bad air days in 2023. Although this was lower than the previous years, it still meant that the air in the city was unbreathable for about 44 per cent of the year (chart 2).

A bad air day is one when the air quality index is 201 or above. Prolonged exposure to such poor-quality air can cause serious health ailments.

The presence of fine particulate matter in Delhi’s air not only increased by 10 per cent in 2023 over the previous year, but the city had more than twice the average levels of pollutants present across India. Delhi’s particle pollution was 20 times the WHO-prescribed annual air quality guidelines. All other major cities in the country in comparison had lower levels of air pollutants in 2023 (chart 3). 

The same year, residents of the Indian capital city spent more than half of their annual hours breathing toxic air, second only to those in Dhaka, the capital of Bangladesh. Those in Islamabad and Beijing were also breathing hazardous air for longer hours in 2023 than before (chart 4).

To reduce this persistence of air pollution, India launched a national-level strategy called the National Clean Air Programme (NCAP) in 2019 to improve air quality in a systematic and time-bound manner.

NCAP was implemented in 132 cities across the country and set an initial target of 20-30 per cent reduction in the concentration of particulate matter by 2024 compared to the 2017 levels. This was later revised upwards to 40 per cent by 2026.

But despite an increase in spending under NCAP, progress in Delhi lags behind other metros. Of the Rs 1,200 crore released under the programme since FY22, over Rs 700 crore has been spent across India in the last three financial years (chart 5).

Delhi accounted for under 2 per cent of this expenditure. Of the Rs 9 crores earmarked for it in FY24, just Rs 5 crores were used. The city is also falling behind other metros in achieving its reduction targets. Mumbai and Ahmedabad have cut their air pollutant levels by over 40 per cent in FY24 compared to FY18. Kolkata, Hyderabad and Bengaluru have also achieved considerable reduction in the same period (chart 6).