The war against air pollution

WHO’S new metric on pollution levels highlights the scale of India’s challenge

The World Health Organization (WHO), on Wednesday, released its revised Global Air Quality Guidelines (AQGS), its first update since 2005. The new AQGS provide an assessment of the health effects of air pollution, set new thresholds for key air pollutants, and provide recommendations to improve air quality. The revision was necessary because, since 2005, there has been fresh evidence that shows harm from air pollution begins at much lower levels than previously thought. According to the new metric, the average 24-hour exposure to PM2.5 must remain below 15µg/m³, down from 25µg/m³. In the case of PM10 particles, the safe threshold has been lowered from 50 to 45µg/m³. The AQGS report adds that air pollution causes seven million premature deaths annually. Disparities in air pollution exposure are increasing worldwide; lowand middle-income countries have growing levels of air pollution because of urbanisation and economic development that relies on the burning of fossil fuels.

The release of the WHO report has raised questions on whether AQGS can be implemented, especially in challenging geo-climatic zones such as India. It is certainly not going to be an easy task, even though air pollution has become politically salient. In comparison to AQGS, India’s threshold levels are many folds higher. According to the 2009 National Ambient Air Quality Standards, the acceptable

PM2.5 exposure limit over 24 hours is 60µg/m³ (four times the new WHO limit), and for exposure over a year-long period, 40µg/m³ (eight times the revised WHO threshold). The 2019 National Clean Air Programme does not have a legal mandate, but aims to achieve a 20% to 30% reduction in PM 2.5 concentrations over 2017 annual levels in over 100 cities by 2024.

There is enough scientific evidence that shows air pollution is not just a health problem, but also impacts economic growth. For example, a study published in The Lancet in 2020 said that Delhi, which faces an annual catastrophe post-diwali, suffered the highest per-capita economic loss due to air pollution in 2019, eroding 1.08% of stage GDP. In addition, overall deaths and disease due to air pollution is linked to a loss of 1.36% of India’s GDP. India must focus on cleaning up its power, industry, and transport sectors, set up interim targets, and plan a more nuanced regional approach to provide the clean air to its citizens.