Urban stormwater pollution is produced by many sourcesL wet and dry deposition import pollutants in the liquid, solid, and gaseous phases. The materials are primarily derived from emissions from industrial sources and from heat and power generating plants. Urban catchment-borne pollutants are generated by vehicular traffic, construction and wrecking works, corrosion of surfaces, animal wastes, and trash of any kind. There are some losses in the pollutant balance from infiltration, wind erosion, degassing, and street cleaning. Some pollutants are permanently stored in the urban catchment. Temporary stored materials are found to be attached to catchment surfaces, accumulated in gully pots, and are pipe deposited. The bulk of pollutants is flushed from the urban catchment in stormwater runoff and contribute to the overall pollution of the receiving water bodies.