ACID RAIN: When the pH of the rain water drops below5.6, it is called acid rain. Acid rain is harmful for agriculture, trees and plants as it dissolves and washes away nutrients needed for their growth. It causes respiratory ailments in human beings and animals. When acid rain falls and flows as ground water to reach rivers, lakes etc. it affects plants and animal life in aquatic ecosystem
SMOG: The word smog is derived from smoke and fog. There are two types of smog: classical and photochemical smog. Classical smog occurs in cool humid climate. It is a mixture of smoke, fog and Sulphur dioxide. It is also called reducing smog. Whereas photochemical smog occurs in warm and dry sunny climate. It has high concentration of oxidizing agents and therefore, it is also called as oxidizing smog
OZONE HOLE: Depletion of ozone layer is known as ozone hole.
EFFECTS OF DEPLETION OF THE OZONE LAYER: With the depletion of ozone layer, more UV radiation filters into troposphere. UV radiations lead to ageing of skin, cataract, sunburn, skin cancer, killing of many phytoplankton, damage to fish productivity etc
WATER POLLUTION:- contamination of water by foreign substances which make it harmful for health of animals or plants or aquatic life and make it unfit for domestic, industrial and agriculture use.
SOURCES / CAUSES OF WATER POLLUTION- � Sewage and domestic wastes � Industrial effluents � Agriculture effluents � Siltation-mixing of soil or rock into water � Thermal pollutants � Radioactive discharge