In 2019, air pollution in India caused the premature deaths of more than a million people. That same year, the government established the National Clean Air Programme. Three years later, the National Clean Air Programme is widely described as ineffective, and India continues to rank among the top five most polluted countries in the world. Now, scientists are looking at a different approach to tackling the country’s toxic air, one based on the recognition that pollution transcends national and state borders. The National Clean Air Programme was formulated to tackle air pollution in cities, specifically to reduce particulate matter (PM2.5)...