The study looked at stormwater runoff in an urban area to see where pollution comes from and how to control it. They found that most of the pollution in the runoff comes from particles like dirt and debris. Factors like the type of land use, traffic, and street cleaning affect the quality of the runoff. The worst pollution was found in old residential areas, followed by places with restaurants, shops, and roads with heavy traffic. To reduce pollution, it's important to clean streets regularly and target specific areas that contribute the most to runoff pollution.