Water Pollution started in the Industrial Revolution of the mid-19th century. By the middle of the 20th century, the effects of these changes were beginning to be felt in countries around the world. In the 1960s, an environmental movement began to form that worked to slow the amount of pollutants flowing into the planet's ecosystems. Out of this movement came events like Earth Day, and legislative victories like the Clean Air Act (1970) and the Clean Water Act (1972).