Urban air quality degradation poses significant risks to human health, particularly affecting the respiratory and circulatory systems, as harmful pollutants penetrate the body upon exposure. Effective management of urban air quality therefore requires systematic monitoring and robust scientific tools capable of assessing emission sources, pollutant dispersion, and population exposure. Air quality models (AQMs) such as AERMOD and CALPUFF have emerged as essential components for understanding pollutant behaviour in complex urban environments. While AERMOD is widely used for short-range dispersion studies and CALPUFF for long-range transport. This talk provides an overview of key urban air quality modelling tools with a focus on AERMOD, discussing their capabilities, limitations, and data requirements—particularly the challenges faced in developing countries due to limited availability of reliable input datasets. Case studies from Chennai and Delhi will be presented to demonstrate practical applications of AERMOD in real urban settings, highlighting the identification of pollution hotspots, assessment of emission sources, and implications for urban planning and policy interventions.