Nestled in the fertile plains of Bihar's Nalanda district, Bihar Sharif occupies a strategic position in the Gangetic Basin, approximately 80 kilometres southeast of Patna. Situated at a modest elevation of around 60 metres above sea level, the city lies on the southern bank of the Panchane River, a tributary of the Ganges, though it lacks significant large water bodies that might aid in pollution dispersion. Its geography is characterised by flat alluvial terrain, typical of the Indo-Gangetic Plain, which traps pollutants due to limited natural ventilation. The urban landscape blends historical significance as an ancient centre of learning with modern urban sprawl, creating a distinct urban–rural gradient where peri-urban areas transition into intensive agricultural zones dominated by rice and wheat cultivation. This agricultural belt contributes to seasonal biomass burning, while the city's location along National Highway 31 and proximity to industrial clusters in neighbouring districts exacerbates vehicular and industrial emissions. The surrounding landscape, devoid of significant topographic relief, allows pollutants to accumulate, particularly during winter when temperature inversions become frequent. Bihar Sharif's position in one of South Asia's most densely populated regions means it experiences compounded pollution from local sources and regional transport, with its air quality intricately linked to the broader atmospheric dynamics of the Gangetic Plain.

Bihar Sharif's air quality follows a pronounced seasonal rhythm dictated by the humid subtropical climate and monsoon patterns. During winter (October to January), pollution peaks dramatically as cold, stagnant air creates persistent temperature inversions that trap pollutants near the surface. Dense fog, common in December and January, further impedes dispersion, while increased domestic biomass burning for heating and agricultural residue burning after the kharif harvest elevate particulate levels. This period poses severe risks, especially for children, the elderly, and those with respiratory conditions, who should minimise outdoor exposure and use air purifiers indoors. Spring (February to March) sees gradual improvement as temperatures rise and winds pick up, though lingering dust from construction and road sources remains a concern. The summer months (April to June) bring extreme heat, which can increase ozone formation, but stronger winds and convective activity help disperse pollutants, making this a relatively better time for outdoor activities, albeit with heat precautions. The monsoon (July to September) offers the cleanest air, as heavy rainfall scrubs the atmosphere of particulates, though high humidity may exacerbate respiratory issues for some. Sensitive groups should monitor forecasts year-round, with winter requiring the most vigilance.