Impact of Air Pollution on Birth Outcomes: Causal Evidence from India

India consistently ranks among the countries with the highest levels of ambient air pollution worldwide. At the same time, it faces significant challenges in neonatal health, with newborns having low average birth weights and a high incidence of being born within the low birth weight (LBW) and very low birth weight (VLBW) category. Using data from the Indian National Family Health Survey (NFHS), we examine the impact of in-utero exposure to particulate matter on a number of birth weight indicators. We exploit variation in wind direction during the in-utero period to capture quasi-random variation in particulate matter exposure for each child. We find that reducing in-utero PM2.5 exposure by one standard deviation would lead to 1.3% increase in average birth weight, a 2.7 percentage point decrease in the incidence of LBW births and a 0.6 percentage point decrease in the incidence of VLBW births respectively. Drawing on estimates from prior studies, we find that the observed improvements in both average birth weight and reductions in LBW incidence from meeting WHO air quality standards could yield substantial long-run economic benefits, potentially amounting to billions of dollars annually in addition to broader gains in child health, cognition, and educational outcomes.