Satellite data from various platforms show that the Himalayas act as a barrier that separates a region of abundant aerosols in the Indo-Gangetic Plains (IGP) from the region of pristine air at high altitude in the Tibetan plateau. This accumulation of abundant aerosols over central Nepal can be attributed primarily to the large scale transport of aerosols and dusts from the IGP. But, since the Himalayas rise steeply from the plains with a series of folds, these complex terrains produce their own local wind flow structure affecting the spatial distribution of the transported pollutants. In this study, we present a numerical simulation of wind flow structure over central Nepal with high-resolution nests over a locally polluted and a pristine valley, and examine its implications for regional aerosol transport , and in particular export to the Tibetan Plateau.