Test: Pollution of Air & Water- 2

Addition of harmful substances in water to make it unfit for human consumption is called water pollution. Harmful substance includes domestic and industrial sewage

The substances that pollute the natural substances like air, water and soil are called pollutant. Exhaust from industries and vehicular emission are some common pollutants.

Water pollution is caused by addition of untreated domestic sewage and industrial wastage in water bodies.

Residential area, park and crop fields are very less polluted areas while industrial areas have large number of factories that emit harmful gases to cause air pollution.

Ponds, river and lake are natural source of water as they are present naturally on earth. On the other hand Canals are manmade source of water especially for irrigation purpose.

Air pollution is caused by combustion of fossil fuels, chimneys of factories and burning of coal. Freezing of ice is not responsible for air pollution.

Burning of fossil fuel produce carbon dioxide gas, Sulphur dioxide gas and Nitrogen oxide gas. Oxygen gas is not produced by burning of fossil fuel.

Rain water is purest form of water as during cloud formation evaporation of water takes place in which impurities are left in water bodies. Spring water, subsoil water and hand pump water contains some salt dissolved in it.

Vegetable peels, cotton cloths and paper are organic wastes as obtained from plants. DDT is insecticide that used to kill insects and pests prepared in laboratory.

River and lake are common source of drinking water. Sea and ocean water are salty and cannot be used for drinking purpose.