Describe various causes of water pollution.

Contamination of water bodies with undesirable substances like fertilizers, pesticides or poisonous substances, thus degrading the water quality and making it unfit for drinking and other purposes is defined as water pollution.

Water pollution occurs from organic pollutants like detergents that are a part of domestic waste, insecticides from farm runoff. Inorganic water pollutants include heavy metals, fertilizers, chemical wastes from industries. Industrial waste into water bodies pollutes the water bodies as majority of the waste is non-biodegradable. Industries also use water for cooling in various operations and later return this hot water to water-bodies therby causing thermal pollution. Sewage waste which is mostly from houses is also dumped into rivers or lakes. Runoff water from farms carries along with it chemicals of fertilizers and pesticides thus again polluting the water bodies.