Using an eight-week-long original survey conducted day by day in Beijing in 2015, we leverage daily variation in air quality to estimate the causal effects of pollution on support for the Chinese regime. Our results show that pollution decreases satisfaction with both central and local governments and increases demand for oversight of government. Additionally, we time our survey to partially coincide with a period during which the government intentionally reduced air pollution, allowing us to exploit a unique instance of authoritarian environmental engineering. We show that government efforts to reduce pollution do successfully improve citizensâ€™ evaluations of the regime. To our knowledge, this article provides the first causal estimates of the challenges to popular support posed by environmental issues in a developing country and also illustrates the specific ways in which public opinion under authoritarian governance is affected by pollution.