NEW DELHI: Prolonged exposure to fine particulate air pollution (PM2.5) is associated with higher risks of depression and anxiety, a nationwide study has found, highlighting how environmental factors are compounding India’s mental health burden even as the Union Budget seeks to strengthen mental health infrastructure.
Led by researchers from IIT Delhi in collaboration with AIIMS New Delhi, NIMHANS and St John’s Medical College, the study was published in the international journal iScience.
Analysing data from 34,802 adults across 12 states, including Punjab, Uttar Pradesh, Rajasthan and Assam, the researchers found that sustained exposure to PM2.5 was linked to an 8% increase in the odds of depression and a 2% rise in anxiety.
The findings are based on clinically diagnosed cases from the National Mental Health Survey (2015–16). As a cross-sectional analysis, the study establishes association rather than causation. Dr Anand Krishna of the community medicine department at AIIMS said this distinction was important, but added that even modest risk increases assume public health significance given the large population exposed to polluted air.
The mental health burden was highest among urban metro residents, people aged 40–49 years, and those from lower-income groups. Regionally, stronger links between pollution and depression were observed in eastern India, while anxiety showed greater association in western states. Risks also peaked during the post-monsoon season, when pollution levels typically rise.
Going beyond overall PM2.5 concentrations, the study examined specific chemical constituents of air pollution. It found that sulphates, nitrates and ammonium—largely generated by traffic, industrial emissions and agricultural activity—were more strongly associated with depression. Elemental carbon, a marker of diesel and fossil-fuel combustion, showed the strongest link with anxiety.
By identifying pollution components and their sources, the researchers said the study offers clear policy relevance, helping prioritise targeted emission control measures at a time when air quality continues to deteriorate across many regions.
The analysis also included participants from Gujarat, Manipur, Madhya Pradesh, Chhattisgarh, West Bengal, Jharkhand, Tamil Nadu and Kerala, using advanced satellite data and atmospheric modelling.
