|University Federico II
of Naples, Italy
An American board for ecology properly defined pollution as "an unfavourable modification of a natural environment, completely or partially due to human activity which, with direct or indirect interventions, modify water physico-chemical characteristics, energy fluxes and the structure and abundance of living associations".
Pollution sources are manifold and are related to human activities, even to those that appear "harmless".
If you like to know more about sources and kinds of pollution then continue...