Pollution is the introduction of a substance that either has harmful or poisonous effects on the environment. The main 3 types of pollution are land, water, and air pollution. Some other types of pollutions are soil, noise, radioactive, light, and thermal pollutions. Water Pollution occurs when toxic substances enter bodies of water and degrade the quality of water. Air Pollution occurs when pollutants such as gases and particles combine into the air and some are even poisonous causing drastic effects to plants, animals, and humans. Land Pollution occurs when waste materials are deposited on land or underground and soon contaminates the soil and groundwater posing a threat to public health.