Prenatal exposure to air pollution and climatic factors associated with adverse birth outcomes in India

Prenatal exposure to ambient fine particulate matter and climatic factors, such as temperature and rainfall, are associated with adverse birth outcomes in India, according to a study published July 2nd, 2025, in the open-access journal PLOS Global Public Health by Mary Abed Al Ahad from the University of St Andrews, U.K.

Ambient air pollution poses a global threat to human health, with a disproportionate burden of its detrimental effects falling on those residing in low and middle-income countries. Referred to as the silent killer, ambient air pollution is among the top five risk factors for mortality in both males and females. With a diameter of less than 2.5 microns, ambient fine particulate matter 2.5 (PM2.5), which primarily originates from the burning of fossil fuels and biomass, is considered the most harmful air pollutant. In the 2023 World Air Quality Report, India was ranked as the third most polluted country out of 134 nations based on its average yearly PM2.5 levels.

Ambient air pollution has been associated with a range of pediatric morbidities, including adverse birth outcomes, asthma, cancer, and an increased risk of chronic diseases. Most studies investigating the association between ambient air pollution and adverse birth outcomes have primarily been conducted in high-income countries. Despite the alarming rise in air pollution levels in India, there has been a paucity of research exploring its impact on adverse birth outcomes.

To address this knowledge gap, the researchers investigated the impact of ambient air pollution on adverse birth outcomes at the national level, focusing on low birth weight and preterm birth, and used different geospatial models to highlight vulnerable areas. The analysis provided evidence of the association between in-utero exposure to PM2.5 and adverse birth outcomes by leveraging satellite data and large-scale survey data. The individual-level analysis revealed that an increase in ambient PM2.5 is associated with a greater likelihood of low birth weight and preterm birth. Climatic factors such as rainfall and temperature were also linked to adverse birth outcomes. Children residing in the Northern districts of India appeared to be more susceptible to the adverse effects of ambient air pollution.

According to the authors, the geostatistical analysis underscores the need for targeted interventions, particularly in Northern districts. In addition, the National Clean Air Program should be intensified, with stricter emission standards and enhanced air quality monitoring. Climate adaptation strategies, such as developing heat action plans and improving water management, should be incorporated into public health planning to mitigate the effects of extreme temperatures and irregular rainfall. Public health initiatives should be implemented to raise awareness of the risks of air pollution and climate change, particularly among pregnant women.