What activity is considered a non-point source of pollution?

Stormwater runoff is recognized as a non-point source of pollution because it originates from multiple diffuse sources rather than a single identifiable point. When rain or snow melts, the water flows over land or impervious surfaces, such as roads and parking lots, picking up various pollutants like oils, heavy metals, sediments, and chemicals along the way. This mixturing of pollutants is difficult to trace back to a specific location, making it challenging to manage and control. In contrast, other options like direct discharge from factories or dumping chemicals represent discrete, identifiable sources that can be regulated directly, classifying them as point sources of pollution.