A point source of pollution is a single ientifiable localized source of air, water, thermal, noise or light pollution. A point source has negligible extent, distinguishing it from other pollution source geometries. The sources are called point sources because in mathematical modeling, they can be approximated as a mathematical point to simplify analysis. Pollution point sources are identical to other physics, engineering, optics and chemistry point sources except that their emissions have been labeled as "polluting". Some examples of point-sources of pollution are: