What is pollution?

Pollution is the entering of contaminants into the natural environment that results in unfavorable or undesired effects to living beings and the environment. Pollution comes in different forms such as chemical substances or energies like sound, light and heat. The pollutants which causes the pollution is either introduced to the source from the outside or it occurs naturally. https://www.youtube.com/watch?v=vP3pbh_-pu8 (pollution, land, air and water)

http://ocean.nationalgeographic.com/ocean/critical-issues-marine-pollution