2. Diffuse or non-point source.

♤ It is from various ill defined and diffuse sources. They vary spatially and temporally and are difficult to regulate.

♤ The main sources of water pollution are as follows:

1) Community waste water: Include discharges from houses, commercial and industrial establishments connected to public sewerage system. The sewage contains human and animal excreta, food residues, cleaning agents, detergents and other wastes.

Putrescibility is the process of decomposition of organic matter present in water by microorganisms using oxygen.

2) Industrial Wastes: The industries discharge several inorganic and organic pollutants, which may prove highly toxic to the living beings.