Which of the following is an example of point-source pollution?

Point-source pollution refers to contaminants that enter the environment from a single, identifiable source. This type of pollution is often easy to monitor and regulate because it originates from a specific location. The example of a factory chimney emitting smoke clearly illustrates this concept, as the chimney represents a distinct point from which pollutants are released into the atmosphere.

In contrast, other forms of pollution, such as fertilizer runoff from agriculture, are categorized as non-point source pollution. This type of pollution is more diffuse, stemming from multiple sources over a larger area, making it more challenging to track and manage. Similarly, airborne contaminants from vehicles and pollution from urban centers also involve numerous sources, thereby fitting into the non-point category. These other examples are more complex because they encompass emissions and runoff contributing to overall pollution levels without a single identifiable origin.