The Deadly Pollutant Hidden in Heat Waves

While discussions about air pollution in India mostly focus on particulate matter, scientists are increasingly raising the alarm about surface ozone, a secondary pollutant that forms naturally when oxides of nitrogen and volatile organic compounds react under high heat and sunlight. Ozone killed more than 400,000 people worldwide in 2019, up 46% since 2000, and India has seen the most increase in ozone deaths over the past decade. Ozone wreaks havoc in the respiratory tract and can reduce plant yields, threatening food security. India's Central Pollution Control Board monitors ozone pollution measurement at 200 micrograms per cubic meter, but ozone is a hyperlocal pollutant, and more than 200 Indian cities don't monitor ozone at all.