Estimating The Health Benefits from Air Quality Improvements in Ahmedabad, India Under the National Clean Air Programme

Outdoor air pollution contributed to an estimated 980,000 deaths in 2019 and imposes an enormous public health burden in India. For many Indian cities, average annual exposures are above the current National Ambient Air Quality Standard (annual average of 40 µg/m3). To provide a roadmap for addressing unhealthy air pollution levels, the Government of India launched the National Clean Air Programme (NCAP) in 2019. The NCAP effort aims to reduce fine particulate matter PM2.5 levels 20–30% by 2024 relative to 2017 levels in 132 cities that are in nonattainment for the annual NAAQS. Ahmedabad,  a city of about 8.5 million people in Gujarat state, in 2017 launched continuous air quality monitoring and has been taking steps to reduce PM2.5 levels through NCAP actions.  We investigated publicly available air quality data for Ahmedabad to evaluate how city air quality has changed during NCAP implementation and deploy an air quality and health impact assessment model to estimate the health effects of city air pollution.

Specifically, we configured the Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) with local air pollution, population, and baseline health data to estimate citywide air quality effects on human health from PM2.5 exposures between 2018 and 2022 using air quality exposure-response functions derived from international epidemiological cohort studies. Overall, we find that the average air quality improved slightly in Ahmedabad during the evaluation period, from 63.4 to 56.2 µg/m3 in 2022, based on available air monitoring data. That decrease represents a 7.2% reduction in annual PM2.5 levels, while attainment of the 30% NCAP goal by 2022 would have resulted in an annual PM2.5 level of 44.4 µg/m3 in 2022. Our health effect analysis in BenMAP-CE are estimates changes in annual all-cause mortality by analyzing population-weighted PM2.5 exposures. We estimate that observed reductions in PM2.5 levels from 2018-2022 are associated with 1631 (95% CI, 1234 - 2010) fewer deaths citywide. However, if the 30% NCAP target had been achieved by 2022, the city would have seen 3931 (95% CI, 2984 - 4834) fewer deaths from PM2.5 exposures. Our integrated air quality and health assessment provides a blueprint for other Indian cities to evaluate how air quality changes affecting human health and shows how a focus on the health impacts of cleaner air can support future NCAP implementation efforts nationwide.