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