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Bilāspur, situated in the fertile plains of Chhattisgarh in central India, occupies a strategic position at coordinates 22.0900°N, 82.1500°E, with an elevation of approximately 264 meters above sea level. This city, the second-largest in Chhattisgarh, lies within the Mahanadi River basin, approximately 100 kilometers north of the state capital Raipur, positioning it as a key urban hub in the region's rice bowl. The terrain is predominantly flat alluvial plains, interspersed with gentle undulations, surrounded by agricultural zones that produce rice, maize, and pulses, contributing to seasonal biomass burning. Bilāspur's location in the Chhattisgarh Plain, flanked by the Maikal Hills to the west and the Chota Nagpur Plateau to the northeast, creates a semi-enclosed basin that can trap pollutants, especially during calm weather conditions. Proximity to the Arpa River, a tributary of the Mahanadi, offers some moderating effects but is insufficient to significantly disperse urban emissions. The city serves as a major railway junction and commercial center, with general urban pollution sources including vehicular traffic, construction activities, and small-scale industries, exacerbated by its position along national highways connecting industrial belts. The urban–rural gradient sees a mix of dense core areas transitioning to peri-urban farmlands, where agricultural residue burning in nearby villages adds to particulate matter, particularly post-harvest. This geographic setting, combined with its role in regional trade and agriculture, directly influences air quality by fostering pollutant accumulation, especially during periods of low wind and temperature inversions.

In Bilāspur, air quality follows a distinct seasonal pattern shaped by the region's tropical climate, with pollution levels fluctuating due to meteorological factors. During winter (November to February), cool temperatures and frequent temperature inversions trap pollutants near the surface, leading to peak pollution episodes; this season is marked by calm winds and fog, which reduce dispersion, making it the least favourable time for outdoor activities, especially for sensitive groups like children, the elderly, and those with respiratory conditions. Spring (March to May) sees rising temperatures and occasional dust storms from nearby arid areas, moderately increasing particulate matter, though increased wind speeds can provide some relief. The monsoon season (June to September) brings heavy rainfall from the southwest monsoon, which effectively washes out pollutants, resulting in the cleanest air of the year; this period is ideal for outdoor pursuits, with reduced health risks. Post-monsoon (October) transitions into drier conditions, with agricultural residue burning in surrounding farmlands contributing to a gradual rise in pollution as winter approaches. Throughout the year, sensitive individuals should monitor local air quality advisories, avoid strenuous activities during high pollution days in winter, and utilize indoor air purifiers when necessary, while the monsoon offers a respite for all residents.