Sasarām occupies a strategic position in eastern India's Rohtas district of Bihar, situated at coordinates 24.9500°N, 84.0300°E along the Grand Trunk Road that historically connected the Gangetic plains to central India. The city lies approximately 150 kilometers southwest of Patna, positioned in the transitional zone between the fertile Indo-Gangetic Plain to the north and the rugged Vindhya Range foothills to the south. At an elevation of roughly 110 meters above sea level, Sasarām rests on relatively flat terrain that gradually slopes toward the Son River basin to the east, creating a subtle urban-rural gradient where agricultural lands intermix with urban development. This location places Sasarām within Bihar's agricultural heartland, surrounded by extensive rice and wheat cultivation that contributes to seasonal biomass burning. The city's proximity to the Son River, approximately 15 kilometers to the east, provides some moderating influence on local microclimate but insufficient to significantly disperse pollutants. Sasarām's urban character reflects a growing secondary city experiencing rapid urbanization without corresponding infrastructure development, resulting in unplanned expansion that traps pollutants in its street canyons. The surrounding landscape—flat agricultural fields to the north and gently rising terrain to the south—creates a basin-like effect that inhibits natural ventilation, particularly during winter months when temperature inversions become frequent. This geographic setting, combined with increasing vehicular emissions from the National Highway 19 corridor and domestic fuel combustion in peri-urban areas, establishes Sasarām as representative of many developing Indian cities where geography exacerbates anthropogenic pollution.

Sasarām's air quality follows a distinct seasonal pattern shaped by the monsoon-dominated climate of eastern India. During winter (December-February), pollution reaches its peak as cold, stable atmospheric conditions create persistent temperature inversions that trap particulate matter near the surface. Morning fog frequently combines with smoke from biomass burning for heating and agricultural residue, reducing visibility and elevating respiratory risks—particularly hazardous for children, elderly residents, and those with pre-existing conditions who should limit outdoor exposure during these months. Spring (March-May) brings gradually improving conditions as temperatures rise and ventilation increases, though occasional dust storms from the Thar Desert can temporarily degrade air quality. The summer monsoon (June-September) offers the cleanest air as heavy rainfall effectively scrubs pollutants from the atmosphere and strong southwesterly winds provide excellent dispersion—this period represents the optimal time for outdoor activities. Post-monsoon (October-November) sees a rapid deterioration as agricultural burning intensifies following the kharif harvest, combining with festive fireworks during Diwali to create hazardous episodes. Sensitive groups should monitor local air quality reports particularly during October-November transition and January inversion periods, using N95 masks when pollution levels spike. The seasonal rhythm demonstrates how meteorological factors—from winter stagnation to monsoon cleansing—interact with human activities to create Sasarām's annual air quality narrative.