Environmental regulations on air pollution in China and their impact on infant mortality.

This study explores the impact of environmental regulations in China on infant mortality. In 1998, the Chinese government imposed stringent air pollution regulations, in one of the first large-scale regulatory attempts in a developing country. We find that the infant mortality rate fell by 20 percent in the treatment cities designated as "Two Control Zones." The greatest reduction in mortality occurred during the neonatal period, highlighting an important pathophysiologic mechanism, and was largest among infants born to mothers with low levels of education. The finding is robust to various alternative hypotheses and specifications. Further, a falsification test using deaths from causes unrelated to air pollution supports these findings.