The fertility dividend of environmental regulations: Evidence from China's Low-Carbon City policy

Amid declining birth rates and the aging population, improving not just the quantity but also the quality of newborns has become increasingly important. Biomedical studies link air pollution to poor birth outcomes, but economic research on regulatory interventions remains limited. Using detailed data and a quasi-experiment on the low-carbon policy in China, we analyze the policy's impacts on fertility quality. We find that the policy increased gestational age by approximately 0.526 weeks and reduced the risk of preterm birth—effects consistent across genders and maternal ages. We show that improvements came through three channels: reduced air pollutants, better maternal health, and improved environmental perception. Our findings link carbon regulation to demographic outcomes in aging societies and highlight environmental policies as a tool to improve fertility quality, offering policymakers win-win strategies to address demographic and environmental challenges: cleaner air today can mean healthier babies—and stronger societies—tomorrow.