Rāja Pākar, nestled in the fertile plains of Bihar, India, occupies a geographically significant position within the Gangetic Basin. Located at approximately 25.7350° N, 85.3376° E, the town’s terrain is predominantly flat, characteristic of the Indo-Gangetic Plain, with an elevation of roughly 55 meters above sea level. This low-lying topography contributes to a tendency for pollutants to accumulate, particularly during periods of atmospheric stability. The surrounding landscape is dominated by agricultural fields – primarily rice and maize cultivation – which, while vital to the regional economy, can contribute to particulate matter through seasonal burning practices. Rāja Pākar’s proximity to the Ghaghara River, though providing a source of water, also influences local humidity and can impact the dispersion of pollutants. The urban–rural gradient around Rāja Pākar is relatively gradual; the town blends seamlessly into the agricultural landscape, meaning that agricultural emissions readily impact the urban air quality. While not directly adjacent to major industrial belts, the town serves as a regional market hub, experiencing increased vehicular traffic and associated emissions. The lack of significant natural barriers, combined with the flat terrain, limits the natural ventilation and dispersal of pollutants, making Rāja Pākar susceptible to localized air quality challenges. The region's climate, characterized by hot summers and a distinct monsoon season, further complicates the atmospheric dynamics influencing air quality.

Rāja Pākar’s air quality follows a distinct seasonal pattern dictated by the region’s monsoonal climate. The pre-monsoon season (March-May) typically witnesses the poorest air quality. Rising temperatures and decreasing wind speeds create conditions conducive to temperature inversions, trapping pollutants close to the ground. Agricultural burning, a common practice to clear fields for the planting season, significantly elevates particulate matter concentrations during this period. The monsoon season (June-September) brings relief, with increased rainfall and stronger winds effectively flushing out pollutants. Humidity also rises, which can affect the composition of airborne particles. The post-monsoon season (October-November) sees a gradual return to drier conditions, and a resurgence of agricultural burning, though often less intense than in the pre-monsoon period. Winter months (December-February) are characterized by cooler temperatures and frequent fog, which further restricts atmospheric mixing and traps pollutants, particularly during periods of calm winds. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during the pre-monsoon and winter months, limiting outdoor exposure and avoiding strenuous activity. The monsoon season generally offers the most favourable conditions for outdoor activities, although periods of heavy rainfall can still impact visibility and air quality due to water droplet scattering. Maintaining awareness of local weather patterns and minimizing exposure to potential pollution sources is crucial for protecting respiratory health throughout the year.