Pollution is when we add things that are harmful to the world. There are different types of pollution: air, water, ground. Pollution is harmful to the world and everything that lives in it.
Scientists are always finding new ways to clean up pollution. Factories use filters to trap the harmful chemicals and take them out of the air and water.
To learn more about pollution, visit this web site:
http://www.factmonster.com/ce6/sci/A0839552.html
Picture by Ainozira
