(a) Explain any three factors responsible for water pollution.

(i) Water pollution is caused by organic and inorganic industrial waste and affluents discharged into rivers.

(ii) The main culprits in this regard are paper, pulp, chemical, textile and dyeing, petroleum refineries, tanneries and electroplating industries.

(iii) These industries let out dyes, detergents, acids, salts, heavy metals like lead and mercury pesticides, fertilizers, synthetic chemicals with carbon, plastics and rubber, etc. into the water bodies.

(iv) Fly ash, phospo- gypsum and iron and steel slags are the major solid wastes in India.

(b) Explain any three factors responsible for air pollution.

(i) Air pollution is caused by the presence of high proportion of undesirable gases, such as Sulphur dioxide and carbon monoxide.

(ii) Air borne particulate materials contain both solid and liquid particles like dust, sprays mist and smoke.

(iii) Smoke is emitted by chemical and paper factories, brick kilns, refineries and smelting plants, and burning of fossil fuels in big and small factories that ignore pollution norms.

(iv) Toxic gas leaks can be very hazardous with long-term effects.

(v) Air pollution adversely affects human health, animals, plants, buildings and the atmosphere as a whole.