Urban air pollution has severe negative effects on health and the economy, especially in developing and industrializing countries, such as China and India. Although the transportation sector is widely acknowledged as among the largest contributors to urban air pollution, quantifying its causal...

Quantifying the effect of transportation on urban air pollution is challenging because decisions to travel are endogenous to air quality. The spread of COVID-19 offers a unique opportunity for causal identification, as the pandemic directly affects decisions to travel and choices of...