In a groundbreaking study published in The Lancet Planetary Health, researchers from multiple institutions, including the Indian Institute of Management & Banaras Hindu University, found worrisome numbers associating high levels of air pollution in ten major Indian towns with a considerable number of deaths each year. The study, which took place over a decade from 2008 to 2019, emphasises the serious public health repercussions of exposure to fine particulate matter (PM2.5), which are particles less than 2.5 micrometres in diameter.

The study focused on cities such as Mumbai, Bengaluru, Kolkata, Chennai, Delhi, Shimla, Ahmedabad, Hyderabad, Pune, and Varanasi. Data surprisingly suggests that increased PM2.5 levels exceeding World Health Organisation (WHO) recommendations cause nearly 33,000 deaths per year, or 7.2% of all deaths in these cities.

Delhi had the greatest rate of attributable deaths, at 11.5%, underscoring the city's severe air quality issues. Shimla had the lowest rate, at 3.7%. The study found a direct association between higher PM2.5 levels and mortality rates, with a 1.42% increase in deaths per 10 μg/m2 increase over two days. When we include local sources of pollution like transportation and industries, the proportion dramatically increases to 3.57% using advanced causal modelling techniques.

Petter Ljungman, a senior researcher at Karolinska Institutet's Institute of Environmental Medicine and study co-author, emphasised the study's findings that local pollution sources are more harmful than regional sources. He emphasised the urgent need for authorities to implement comprehensive, year-round actions to alleviate this important threat to public health.

The study found that the WHO's recommended daily limit of 15 μg/m2 for PM2.5 was surpassed on 99.8% of days in the cities tested. In India, where the national limit is set significantly higher at 60 μg/m3, even lower pollution levels were associated with increased mortality risks, raising questions about the sufficiency of the present regulatory requirements.

Jeroen de Bont, a postdoctoral researcher at the Karolinska Institutet and another key author, dismissed the idea of a safe threshold for air pollution and advocated for a revision of India's PM2.5 limit value. He emphasised that the study's findings clearly indicate the acute health concerns presented by daily changes in pollution levels.

The study, done in partnership with international academics from Harvard University, Boston University, and Indian organisations as part of the CHAIR-India consortium, sought to provide comprehensive data for evidence-based policies to reduce air pollution and protect public health in India.

These findings are a strong call to action for policymakers to prioritise rigorous measures to reduce air pollution and protect vulnerable populations. As India faces this ongoing dilemma, the study emphasises the critical need for quick and sustained action to reduce the fatal effects of air pollution on its inhabitants.

This report's publication represents a significant step forward in understanding and mitigating the effects of air pollution, calling on stakeholders from all sectors to work together to achieve cleaner air and healthier communities.