Geospatial Analysis of Air Pollution Sources and Their Impact on Public Health and the Environment in Western Uttar Pradesh, India

Western Uttar Pradesh is among the most severely polluted regions of India, a condition driven by rapid urbanisation, dense vehicular traffic, an extensive small-scale manufacturing base and seasonal agricultural biomass burning. This review synthesises ambient air quality data for seven urban centres (Ghaziabad, Noida, Meerut, Agra, Firozabad, Saharanpur and Muzaffarnagar) from 2020 to 2026, covering the Air Quality Index (AQI) and six criteria pollutants. Particulate concentrations remain persistently above Central Pollution Control Board and World Health Organization reference values, with winter maxima and monsoon minima at every site. Two patterns run counter to the assumption of uniform deterioration: particulate loadings have fallen at most sites since the 2021–2022 peak, whereas ozone and nitrogen dioxide have risen sharply and now define the region's principal remaining risk. The particulate improvement is confined to the coarse fraction, so total mass has fallen while the respirable combustion fraction has not. The review also examines three processes that remain poorly characterised for the region: the possible role of airborne microplastic fibres in road and construction dust as carriers of adsorbed heavy metals; fugitive, non-stack emissions from informal micro, small and medium enterprise clusters, which chimney-based compliance monitoring cannot capture; and the mixing of agricultural residue smoke from the north-west with urban industrial plumes. Because no localised measurements of these processes exist for Western Uttar Pradesh, they are presented as evidence gaps and as a measurement agenda, not as quantified findings. Monitoring must be widened beyond the criteria-pollutant, single-city model towards regional airshed management.