Saharsa Air Quality Index (AQI)

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Saharsa, situated in the northeastern plains of Bihar at coordinates 25.8800°N, 86.6000°E, lies within the fertile Gangetic alluvial basin, a region characterised by its flat topography and minimal elevation variation, typically around 40-50 meters above sea level. This low-lying terrain, coupled with its proximity to the Kosi River—often termed 'the sorrow of Bihar' due to its frequent flooding—creates a geographical setting that profoundly influences air quality. The city's urban character blends densely packed residential areas with surrounding agricultural zones, where rice and wheat cultivation dominate, leading to significant post-harvest burning. Saharsa's location in the Mithila region places it within an urban-rural gradient where traditional biomass use for cooking and heating is prevalent, exacerbated by limited industrial regulation. The absence of major water bodies beyond the Kosi River means there are few natural ventilation corridors, while the surrounding agricultural belt contributes to regional haze from stubble burning. Brick kilns, often unregulated, dot the periphery, adding to particulate emissions. This combination of flat terrain, agricultural intensity, and domestic pollution sources creates a geographical trap where pollutants accumulate, particularly during calm weather conditions, making Saharsa's air quality challenges deeply rooted in its physical and human geography.

In Saharsa's humid subtropical climate, air quality follows a distinct seasonal pattern driven by meteorological factors and human activities. During winter (October to January), pollution peaks due to a combination of agricultural residue burning post-harvest, domestic biomass burning for heating, and meteorological conditions like temperature inversions that trap pollutants near the ground. Dense fog, common in December and January, further exacerbates this by mixing with particulate matter, reducing visibility and increasing health risks. Sensitive groups, such as children, the elderly, and those with respiratory conditions, should avoid prolonged outdoor exposure during these months, especially in early mornings when inversion layers are strongest. The monsoon season (June to September) brings relief as heavy rains wash pollutants from the air, though flooding can occasionally stir up sediments. Spring (February to May) sees moderate pollution levels, but extreme heat in April and May can increase ozone formation from vehicle exhaust. For outdoor activities, the monsoon months offer the cleanest air, while winter should be approached with caution, using masks and limiting strenuous activities. Year-round, local sources like brick kilns and open waste burning contribute to baseline pollution, making air quality a persistent concern across seasons.