Modelling Health Benefits from COVID-19 Produced Cleaner Air in India’s Megacities

India has one of the highest public health burdens attributable to air pollution globally. Despite national air quality regulations and control policies, improvements in air quality have been limited, restricting opportunities to evaluate the health benefits of cleaner air under real-world conditions. COVID-19 lockdowns substantially reduced air pollution in India’s megacities, creating a natural experiment for assessing pollution-attributable health benefits. Using ambient PM2.5 concentration data from United States Embassy and Consulate monitors in Chennai, Hyderabad, Kolkata, Mumbai, and New Delhi during the 2020 and 2021 lockdowns, and World Health Organization AirQ+ software, we estimated the short- and long-term health benefits of maintaining lockdown-related improvements in air quality. PM2.5 reductions ranging from 28–77% during the first lockdown, if sustained long term, would lead to about 42,778 fewer premature deaths in the short term and 132,000 fewer annual avoidable deaths from all causes under the modeled scenario across the five cities. We also estimated annual reductions of 11,100 deaths from chronic obstructive pulmonary disease, 3900 from lung cancer, 5500 from ischaemic heart disease, 3900 from stroke, and 1240 from acute lower respiratory infection. These findings support stronger air quality standards, emission controls, and policy enforcement to reduce air pollution-related mortality in Indian megacities.