Urban Air Pollution in Five Major Cities of Rajasthan, India: Spatiotemporal Assessment Using Multi‐Pollutant Indices

Abstract

Rapid urbanization, industrial expansion, and desert dust transport make India's arid and semiarid cities among the most pollution‐burdened globally. However, chronic multi‐pollutant exposure remains poorly characterized through integrated multicity assessments, despite its role in increasing risks of respiratory disease, cardiovascular morbidity, and premature mortality. This study presents a comprehensive spatiotemporal assessment of ambient air quality across five National Clean Air Programme (NCAP) cities of Rajasthan during 2019–2024. Six years of monitoring data for six criteria pollutants (PM 2.5 , PM 10 , NO 2 , SO 2 , CO, and O 3 ) were integrated with geographic information system (GIS)‐based spatial analysis. Four composite indices—air quality index (AQI), pollution load index (PLI), air pollution index (API), and health index (HI)—were also employed to evaluate pollution dynamics, cumulative pollution burden, and associated health risks. Results revealed persistently elevated particulate pollution, with annual PM 2.5 reaching 81.6 µg m −3 in Jodhpur and exceeding 55 µg m −3 in Jaipur and Kota, whereas PM 10 peaked at 170.2 µg m −3 . Concentrations peaked during winter and post‐monsoon seasons due to atmospheric stability and declined sharply during monsoon through wet scavenging. SO 2 and CO remained within Central Pollution Control Board (CPCB) regulatory limits, whereas O 3 exhibited distinct pre‐monsoon photochemical peaks. Multi‐index analysis identified Jodhpur as most pollution‐burdened city (AQI up to 179; HI >4.5). Persistent spatial differences among cities exceeded interannual variability, highlighting structural and climatic drivers. These findings indicate that short‐term or pollutant‐specific interventions alone are insufficient for sustained air quality improvements. Effective NCAP implementation in climatically vulnerable arid environments demands regionally coordinated, multi‐sector strategies addressing both anthropogenic emissions and background dust contributions.