Who Breathes Worse? Socio-economic Deprivation and PM2.5 in India

Simran Koul 

Air pollution in India has intensified rapidly, alongside substantial population growth across regions with highly uneven socioeconomic and developmental conditions. Ambient fine particulate matter (PM2.5) is among the leading environmental contributors to premature mortality in India, where national average concentrations exceed the World Health Organization guideline by an order of magnitude. National-scale studies have further documented that this burden falls unevenly, with socially disadvantaged populations concentrated in districts recording higher PM2.5 concentrations, making the unequal distribution of exposure an issue of environmental inequity as well as public health. Existing studies of this disproportionate exposure, however, have relied on outdated census-based sociodemographic data or on sample surveys that lack sufficient geographic coverage and spatial granularity. My study addresses these limitations by employing gridded datasets that integrate high-resolution satellite and sociodemographic data to examine how social deprivation is associated with district-level concentrations of total and source-specific PM2.5 across 635 districts in India. I use five of the six indicators from the Global Gridded Relative Deprivation Index (GRDI), a globally standardized measure of multidimensional social deprivation, and implement multiscale geographically weighted regression, allowing each association to vary across space. The associations vary in strength and direction across districts rather than following a single national gradient. The most consistent is the trend in nighttime light intensity, which is negative in 85% of districts, so concentrations tend to be higher where recent development has been slower. Built-up area is negative in three quarters of districts, indicating that, compared with their neighbors, less built-up districts carry comparable or higher exposure. The association with infant mortality divides regionally and is positive across the northern plains, where national concentrations are highest. The same spatial variability holds within each of the nine emission source categories, with the strongest deprivation-aligned associations found for residential PM2.5. These findings indicate that the relationship between social deprivation and PM2.5 exposure in India is regionally structured, and support the case for equitable air quality policies matched to regional source profiles.