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Nestled in the mineral-rich Koriya district of northern Chhattisgarh, Chirmiri occupies a strategic position within India's coal heartland, approximately 300 kilometres north of the state capital Raipur. The city sits at an elevation of around 600 metres above sea level in the Maikal Hills, part of the broader Satpura Range, which creates a basin-like terrain that significantly influences its air quality. This topography acts as a natural amphitheatre, trapping pollutants from local sources and limiting their dispersion. Chirmiri is surrounded by dense forests and coal mines, with no major rivers or large water bodies in immediate proximity to help cleanse the atmosphere. The urban area itself represents a compact settlement within a predominantly rural and industrial landscape, characterised by a sharp urban–rural gradient where mining operations and transport corridors intersect residential zones. Located in the Hasdeo River basin, the region forms part of the Central Indian coalfields, making Chirmiri a hub for coal extraction, handling, and transportation. This geographic setting, combined with its position in a tropical wet-and-dry climate zone, creates a perfect storm for air pollution accumulation, as the surrounding hills inhibit wind flow while local emissions from mining, vehicles, and domestic activities concentrate in the valley.

Chirmiri's air quality follows a distinct seasonal pattern driven by its tropical wet-and-dry climate and local emission sources. During the winter months from November to February, pollution peaks dramatically due to a combination of meteorological factors and human activities. Cooler temperatures lead to frequent temperature inversions, where a layer of warm air traps cooler air—and pollutants—near the surface, while calm winds and morning fog further inhibit dispersion. This period coincides with increased domestic biomass burning for heating and heightened coal mining operations, making outdoor activities particularly hazardous, especially for sensitive groups like children, the elderly, and those with respiratory conditions. The summer months from March to June bring extreme heat, which can elevate ground-level ozone formation from vehicle exhaust, though stronger daytime winds and convective mixing often provide some relief by dispersing particulate matter. The monsoon season from July to September offers the cleanest air, as heavy rainfall from the southwest monsoon washes pollutants from the atmosphere and suppresses dust. However, this period brings flooding and thunderstorms, posing other weather hazards. Post-monsoon months in October see a gradual return of pollution as dry conditions resume and mining activities intensify ahead of winter. Residents are advised to limit outdoor exertion during peak pollution months and monitor local air quality advisories year-round.