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Rajpur Sonarpur occupies a strategic position in the southern fringes of the Kolkata Metropolitan Area in West Bengal, India, situated on the eastern bank of the Hooghly River approximately 15 kilometres south of Kolkata's urban core. This location places it within the expansive Ganges-Brahmaputra delta, characterised by flat alluvial plains with minimal elevation variation, typically just a few metres above sea level, which profoundly influences its air quality dynamics. The city's geography is defined by its transition from dense urban settlements in the north to more peri-urban and rural landscapes towards the south, creating a distinct urban–rural gradient where agricultural zones intermix with residential and commercial developments. Proximity to the Hooghly River and numerous smaller water bodies, including canals and ponds, contributes to high humidity levels that can trap pollutants near the surface. Rajpur Sonarpur lies within the broader industrial belt extending south from Kolkata, with small-scale manufacturing units and informal industries contributing to local emissions, while its position in the delta makes it susceptible to pollution transport from both the megacity to the north and agricultural burning in surrounding rural areas. The flat terrain inhibits natural ventilation, allowing pollutants from vehicle exhaust, road dust, construction activities, and waste burning to accumulate, exacerbated by the city's rapid urban expansion that replaces green spaces with impervious surfaces, reducing natural air purification.

The air quality in Rajpur Sonarpur follows a pronounced seasonal cycle driven by its tropical wet-and-dry climate and regional meteorological patterns. During the winter months from November to February, pollution peaks dramatically due to a combination of factors: cooler temperatures lead to frequent temperature inversions that trap pollutants close to the ground, while calm winds and high humidity foster dense fog and haze that amplify particulate matter concentrations. This period coincides with increased waste burning for warmth and agricultural residue burning in surrounding areas, making outdoor activities particularly hazardous, especially for sensitive groups like children, the elderly, and those with respiratory conditions who should limit exposure and use protective masks. The pre-monsoon season from March to May brings extreme heat and occasional nor'westers (violent thunderstorms) that can temporarily clear the air through strong winds and rainfall, but high temperatures also accelerate photochemical reactions that may increase ozone levels. The monsoon from June to September offers the cleanest air as heavy rainfall scrubs pollutants from the atmosphere and strong southwesterly winds disperse emissions, making this the most favourable time for outdoor activities despite high humidity. Post-monsoon months in October see a gradual deterioration as rainfall ceases and pollution begins to accumulate again, signaling the approach of the hazardous winter period.