Pollution is defined as the discharge of harmful substances that contaminate the air, water or soil. Pollution occurs when substances detrimental to living organisms are introduced into the environment. It can be caused by natural or man-made sources. 1 This website focuses on the environmental contamination that results from human activities. Humans have been degrading the environment for millennia. Increasing industrialization worldwide has contributed to many of the environmental consequences we now face today. 2 This website touches upon the three major categories of pollution, including air, water and soil pollution, each of which pose alarming risks to the global environment. The video below provides a brief introduction on these three types of contamination.