In August 2022, the Union Minister of State for Environment highlighted that there is no established mechanism for ranking cities in terms of pollution in response to the ‘Environmental Performance Index’. The index developed by the Yale Center for Environmental Law and Policy ranks countries on climate change performance, environmental health, and ecosystem vitality on the basis of 40 performance indicators across 11 issue categories. According to this index, India performed the worst and ranked last in the list of 180 countries.

While we do not have an index, the Central Pollution Control Board publishes a list of cities with their AQI levels and the dominant pollutant in the air on a daily basis. This AQI is often treated as a scale to compare the cities with each other. Based on this data, it was recently released in the news that Bihar now houses 7 out of 10 most polluted Indian cities. The data was sourced from the daily update released for AQI levels on 14 November by the CPCBI.

It was argued by the Union Minister of State for Environment that the Yale index used extrapolated indices and is based on unscientific methods and thus cannot be trusted as a valid source. Globally, the recently updated WHO guidelines (2021) dictates that the average annual PM 2.5 concentrations should be no higher than five micrograms per cubic meter. In the IQair report published March 2022, the concentration in 93 per cent of the cities was 10 times the new guidelines and this was the case in 48% of India’s cities.

India’s own pollution guideline ‘National Ambient Air Quality Standards’ (NAAQS), set 12 years ago, requires average annual PM 2.5 concentration to not be higher than forty grams per cubic meter which is eight times the requirement of the WHO guidelines. A review of NAAQS has been sanctioned to a joint team led by IIT Kanpur and the guidelines are set to be updated by next year.

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