What are the causes of water pollution? Discuss how you can contribute in reducing water pollution.

Water pollution can be caused by addition of 

(i) undesirable substances like fertilizers and pesticides or any poisonous substances.

(ii) sewage directly entering a water body.

(iii) hot water from the power plant that increases the temperature and reduces the dissolved oxygen in water thus killing the aquatic organisms.

(iv) industrial effluents or radioactive substances in water body. 

We can take following measures to check water pollution

(i) The sewer lines should not be directly connected to the water body.

(ii) We should not throw our garbages or domestic waste in the water body.

(iii) Prevent dumping of toxic compounds in the water bodies.

(iv) Washing of clothes should be avoided near water bodies as it adds lot of detergents to it.

(v) Plant trees near the banks of the river to check soil erosion otherwise erosion leads to siltation of water body.

See text for causes of water pollution.
Reduction in water pollution.
(i) Sewage: The authorities can be persuaded not to pass untreated effluents into water body. Dairy owners of city can be prevailed upon not to pass dung of cows and buffaloes into municipal waste water lines especially during monsoon days.
(ii) Garbage. Domestic waste or garbage should not be thrown on the banks of water bodies.
(iii) Industrial effluents. Asking the industrial houses not to release untreated effluents into water body.
(iv) Washing clothes. Washing clothes should be discouraged on the banks of water bodies as detergents are source of entrophication.
(v) Vegetation cover. Grasses, herbs, shrubs, and trees should be planted onthe banks of water bodies. This wil check soil eroson and siltation of water bodies. It may reduce runoff from crop fields. Such runoffs are often laden with fertilizers and toxic pesticides which are potent water pollutants.