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Sāhna, a small town nestled in the fertile plains of Punjab, India, occupies a geographically significant position within the Indo-Gangetic Plain. Located at approximately 30.43° N, 75.38° E, its coordinates place it squarely within a region characterized by flat, alluvial terrain formed over millennia by the Indus and Ganges river systems. The surrounding landscape is predominantly agricultural, a patchwork of cultivated fields supporting Punjab’s renowned agricultural output, particularly wheat and rice. This intensive farming contributes to seasonal agricultural burning, a significant factor in regional air quality. Sāhna’s elevation is relatively low, around 238 meters (781 feet) above sea level, which, combined with the flat topography, limits atmospheric dispersion of pollutants. The town sits within a broad urban–rural gradient, transitioning from the denser urban areas of larger Punjab cities towards more sparsely populated agricultural zones. While Sāhna itself is a small settlement, it’s situated within a wider network of towns and villages, contributing to a regional pollution profile. The lack of significant natural barriers, such as hills or mountains, further exacerbates the issue, allowing pollutants to accumulate. Proximity to industrial belts in nearby cities, though not immediately adjacent, also influences air quality through long-range transport of emissions. The climate, characterized by hot summers and cool winters, further impacts atmospheric stability and pollutant behaviour, influencing the formation of temperature inversions and fog, both of which trap pollutants near the ground.

Sāhna’s air quality follows a distinct seasonal pattern dictated by meteorological conditions and agricultural practices. The dry winter months (November to February) are typically the most challenging. Cold temperatures frequently lead to temperature inversions, where a layer of warm air traps cooler air and pollutants near the surface, resulting in stagnant air and elevated particulate matter. Dense fog, common during this period, further restricts visibility and exacerbates the problem by absorbing pollutants. Agricultural burning, a widespread practice to clear crop residue after the harvest of rice and wheat, peaks during this time, releasing substantial amounts of smoke and particulate matter into the atmosphere. Spring (March-May) sees a gradual improvement as temperatures rise, and winds become more frequent, aiding in pollutant dispersion. However, dust storms originating from the Thar Desert can occasionally impact air quality. The monsoon season (June-September) brings relief with increased rainfall, which helps to wash pollutants from the air. However, heavy rainfall can also lead to waterlogging and the release of methane from flooded fields. Finally, the hot summer months (October) often experience a slight improvement in air quality due to increased wind speeds and convective mixing, although high temperatures can still contribute to ozone formation. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during the winter months, limiting outdoor activity and using air purifiers when possible. During periods of agricultural burning, staying indoors with windows closed is advisable.