Imphal, the capital city of Manipur in northeastern India, occupies a distinctive geographic position that profoundly shapes its air quality dynamics. Nestled within the Imphal Valley at an elevation of approximately 790 meters above sea level, the city is encircled by lush, forested hills of the Manipur River basin, creating a natural amphitheater that traps pollutants. This valley setting, with the Loktak Lake to the south—the largest freshwater lake in Northeast India—and the Manipur River flowing through, contributes to localized humidity and fog formation, which can exacerbate particulate matter accumulation. Imphal serves as the urban core of Manipur, transitioning sharply from dense urban settlements to surrounding agricultural lands and rural villages, where practices like jhum (shifting) cultivation are prevalent. The city's location in a seismically active zone, with the Indo-Burma Range to the east, adds geological complexity but minimal industrial activity, as the region lacks major industrial belts. Instead, air pollution stems primarily from anthropogenic sources within the valley: vehicle emissions from growing motorization, road and construction dust from urban expansion, and biomass burning for domestic energy and agricultural clearance. The terrain's bowl-like structure, combined with subtropical highland climate, often leads to temperature inversions, particularly in cooler months, hindering pollutant dispersion and resulting in heightened air quality challenges unique to this isolated yet vibrant urban center in South Asia.

Imphal's air quality follows a pronounced seasonal rhythm, driven by its subtropical highland climate and local emission patterns. During the winter months from November to February, pollution peaks sharply due to a combination of meteorological and human factors. Cool temperatures and frequent temperature inversions trap pollutants close to the ground, while low wind speeds and dense fog—common in the valley—further inhibit dispersion. This period coincides with increased domestic biomass burning for heating and agricultural burning from jhum cultivation in surrounding areas, making outdoor activities particularly hazardous, especially for sensitive groups like children, the elderly, and those with respiratory conditions. Spring (March to May) sees gradual improvement as temperatures rise and winds pick up, though occasional dust from construction and pre-monsoon activities can cause spikes. The monsoon season from June to September brings substantial relief, with heavy rainfall washing pollutants from the air and strong winds aiding dispersion, making this the best time for outdoor pursuits. Post-monsoon autumn (October) marks a transition, with reducing rainfall and rising pollution levels as burning activities resume. Health guidance emphasizes avoiding strenuous outdoor exercise during peak pollution months, using air purifiers indoors, and monitoring local air quality advisories to mitigate risks from particulate matter and other pollutants prevalent in Imphal's seasonal cycle.