a) Automobiles and industries.
b) Air pollution can cause lung diseases like emphysema etc. It can also lead to cancer in humans. Air pollution causes acid rain which is very harmful to plants. Death of trees due to drying because of toxic substances like sulphur dioxide in the air.
c) Planting trees can help check air pollution in and around the school. Use of bicycles as a mode of transport to school or promoting the use of public transports.