evaluation approach which leverages economic theory and machine learning for counterfactual prediction. Our results indicate that …

We use worldwide satellite data to analyse how population size and density affect urban pollution. We find that density … significantly increases pollution exposure. Looking only at urban areas, we find that population size affects exposure more than … itself. We analyse heterogeneity by geography and income levels. By and large, the influence of population on pollution is …

efficient in controlling pollution when there is no uncertainty. We show that this is not the case if some consumers (firms …, local governments) are morally concerned about pollution and the pollution price is inefficiently low for political reasons … to reduce pollution, while price regulation makes these efforts effective. …