This study investigates the causal effects of long-term PM2.5 exposure on COVID-19 deaths, fatality rates and cases in India by using an instrumental variables approach based on thermal inversion episodes. The estimation results indicate that a 1% increase in long-term exposure to PM2.5 leads to an increase in COVID-19 deaths by 5.7 percentage points and an increase in the COVID-19 fatality rate by 0.027 percentage points, but this exposure is not necessarily correlated with COVID-19 cases. People with underlying health conditions such as respiratory illness caused by exposure to air pollution might have a higher risk of death following SARS-CoV-2 infection. This finding might also apply to other countries where high levels of air pollution are a critical issue in terms of development and public health.