The quality of the year that we breathed in the Summer of 2022 was much worse than what we breathed in 2021, across the country. The comparison of the level of pollutants — Particulate Matter (PM) 2.5, PM 10 and Nitrogen Dioxide (NO2) says this. The data from the Central Pollution Control Board (CPCB) were tracked and captured by the National Clean Air Programme (NCAP) Tracker, which was developed by advocacy think tank Climate Trends and Urban Sciences.

In the summer that went by, the situation was the worst in Delhi, where the average PM 2.5 levels in summer (March to June) was 86.6. It is an 18.9 per cent rise from last year’s summer. CPCB’s annual average safe levels of the particle is 40. Cities in the northern part of the country, Lucknow, Jodhpur and Patna exhibited PM 2.5 levels above 70 this summer. In Patna, it was 106.52 in March and in Delhi, it was 105.19 in April. PM 2.5 are minute particles on air which are known to enter the lungs and from thereon the blood stream, causing health issues.

These cities, especially Delhi, had extreme high levels of PM 10, another harmful pollutant too in its air during this summer. In Delhi, the summer levels of PM 10 were 249.94 on an average, the highest being in April — 291.12. It was quite bad in Patna, Jodhpur and Lucknow too. The prescribed annual average safe levels of this pollutant, similar to that of PM 2.5 (but bigger in diameter) are 60. The concentration of Nitrogen Dioxide, an extremely toxic gas, was also high in Delhi and Chandigarh. It was 42.6 in Chandigarh and 41.58 in Delhi in summer, while the annual average safe levels are 40. Chandigarh saw a 90 per cent increase in the concentration of NO2, compared to 2021 summer. It has, however, come down in Lucknow and Patna.

A breath of fresh air

The people who breathed fresh air, despite the humid sun, were Chennaiites. The air pollutant levels in Chennai were safer compared to the other metros and big cities. The PM 2.5 levels were just 24.33 in the southern city, even though the pollution levels have gotten worse, compared to 2021, with a 5 per cent increase. PM 10 and NO2 levels too were the lowest in Chennai, at 60.44 and 12.01. However, no major city in India had safe PM 10 levels in its air. Bengaluru too had comparatively low PM 2.5 levels — 35.13. Its PM 10 levels were 75.57 and NO2 concentration in air was 19.54.

However, going by the Air Quality Index, as of July 7, 2022, Thoothukkudi in Tamil Nadu has the cleanest air in the country, with an AQI value of zero. It is followed by Ghughus in Maharashtra.

Causes and repercussions

Outdoor air pollution has become the fifth largest killer in India after high blood pressure, indoor air pollution, tobacco smoking, and poor nutrition, according to a Global Burden of Disease report. Major reasons attributed to this are stubble burning, motor vehicle smoke emissions, climate change and industries flouting emission norms.