Nauhata, a small city nestled in the heart of Bihar, India, occupies a geographically significant position within the Indo-Gangetic Plain. Located at coordinates 25.9971°N, 86.4887°E, the city’s terrain is largely flat, characteristic of the alluvial plains formed by the Ganges and its tributaries. The surrounding landscape is predominantly agricultural, dominated by rice paddies and wheat fields, reflecting Bihar’s strong agrarian economy. Nauhata’s elevation is relatively low, contributing to the potential for temperature inversions that trap pollutants. The proximity to the Ganges River, while providing a vital water source, also introduces humidity which can exacerbate particulate matter suspension. While not directly within a major industrial belt, the increasing regional industrial activity, particularly brick kilns and small-scale manufacturing in nearby areas, contributes to background pollution levels. The urban-rural gradient is quite sharp; Nauhata itself is a relatively compact urban centre, quickly transitioning to rural farmland. This proximity means agricultural practices, including crop residue burning, significantly impact local air quality. The city’s location within the densely populated Bihar state further compounds the challenges, as population density correlates with increased emissions from domestic sources and transportation. Understanding this interplay of geography and human activity is crucial for addressing Nauhata’s air quality concerns.

Nauhata experiences a distinct seasonal air quality pattern dictated by the monsoon and post-monsoon weather systems. The summer months (April-June) see a build-up of particulate matter due to dry conditions, road dust, and potential agricultural fires preparing fields for the monsoon. High temperatures promote photochemical smog formation, though humidity limits its severity. The monsoon season (July-September) generally brings temporary relief, as rainfall washes away pollutants and increases atmospheric moisture, suppressing dust. However, increased humidity can also foster mold growth, impacting respiratory health. Post-monsoon (October-November) is often the worst period for air quality. Stagnant air, coupled with cooler temperatures and temperature inversions, traps pollutants from crop residue burning – a widespread practice after the harvest – and Diwali celebrations. December-February brings cooler, drier air, with moderate pollution levels sustained by domestic fuel burning for heating and cooking. Sensitive groups – children, the elderly, and those with respiratory conditions – should avoid strenuous outdoor activity during October-November. March-April also requires caution. The monsoon months offer the most favourable conditions for outdoor activity, but vigilance regarding waterborne diseases is essential.