What is environmental pollution? What are the main causes of pollution?

The addition of any undesirable material to air, water and soil from a natural source or due to human activity which adversely affects the quality of the environment is called environmental pollution. The undesirable material thus added to the environment is called a pollutant. Environmental pollution affects human beings, animals, plants and materials.
Main causes of pollution: Main causes of pollution are:
(i) Fast population growth
(ii) Use of pesticides in agriculture
(iii) Rapid industrialisation
(iv) Excessive industrialisation.