Air pollution is one of the extreme ecological threat to the human wellbeing. Previous studies have provided proof that maternal exposure to air pollution throughout pregnancy increases the hazard of adverse birth outcomes. Exposure to air pollution throughout pregnancy and its impact on children in utero is an emerging literature. The current study aims to investigate the impacts of air pollutants i.e. PM2.5, SO2, CO, NO2 and ozone on birth outcomes, especially birth weight and birth size, in various districts of Punjab, Pakistan. Using linear probability model, the results suggest that in-utero exposure to PM2.5, SO2, CO, NO2 reduces the birth weight but ozone increases the birth weight. In case of birth size, the first four indicators of air pollution increased then the probability of smaller birth size whereas ozone reduces this probability. Supervisor:- Dr. Muhammad Nasir