Causes of Acid Rain
The main cause of Acid rain is man made pollution. Huge amount of sulphur-dioxide released due the burning of fossil fuel like coal, petroleum etc.
Nitric oxide (NO) forms when Nitrogen reacts with Oxygen in high temperature in the thermal power station and metal extracting factory and this Nitric oxide reacts with the Oxygen of the air and produce Nitrogen dioxide.
In this way Sulphur dioxide and Nitrogen dioxide react with the water-vapor of the air and produce Sulphuric acid (H2SO4) and Nitric Acid (HNO3) which mix with rain water and fall in the forms of acid rain on the earth.
After falling on the earth, acid rain increase the alkalinity and the salinity of the soil and decrease the fertility of soil.