The increasing demand for electricity worldwide has caused a corresponding rise in the consumption of coal, leading to an increase in sulfur dioxide (SO2) pollution levels. Despite the severity of the issue, there is a lack of conclusive evidence establishing a causal link between SO2 pollution and health, particularly in developing countries. We leverage a large national environmental regulation policy, implemented in China to reduce SO2 emissions, to estimate the impacts of SO2 pollution on mortality. We find that 1-μg/m3 reduction in SO2 concentrations leads to 18 fewer cardiovascular deaths per 100,000 people aged 60 years and above (0.9% decrease) and 2 fewer deaths per 100,000 children under the age of 5 (1.5% decrease) annually. A back-of-the-envelope calculation suggests that the total health benefits of the environmental policy outweigh its economic costs. The results are consistent across various robustness checks.