The concentrations of key trace gases and aerosols are increasing rapidly in the atmosphere of South Asia owing to growing population and associated increase in human activities. These rising concentrations can potentially affect the air quality, atmospheric chemistry, agriculture, ecosystems, freshwater resources and climate, and therefore pose a serious threat to the health, food and water security of billions of people living in South Asia. A recent study shows that premature mortality rates in South Asia due to air pollution are among highest in the world. Therefore, it is very important to understand the processes controlling the distribution and variability of pollutants in this region. However, the available in situ observations of trace gases and aerosols lack sufficient space-time coverage to address this problem and thus use of chemical transport model results and satellite observations becomes essential to advance our understanding of air pollution in this region. In this talk, I will begin with an overview of air pollution problem in South Asia and show how this problem is different from what other parts of the world are facing. Next, I will illustrate the potential of Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to help the interpretation of in situ and satellite observations in South Asia through application of WRF-Chem to three problems of scientific interest. These include simulations of wintertime carbon monoxide (CO) pollution, a typical pre-monsoon season dust storm, and black carbon aerosol distribution. In the end, I will highlight the scope of improvement in present set-up of WRF-Chem and present an outlook towards future research in South Asia.