Pollution is the introduction of contaminants into the natural environment that causes adverse change.

Pollution can take many forms, including:

• Air pollution: The release of pollutants into the air that are harmful to human health and the environment. Source
• Water pollution: The contamination of water bodies, usually as a result of human activities. Source
• Land pollution: The degradation of the Earth’s land surface through misuse of soil resources. Source
• Noise pollution: Exposure to elevated sound levels that may cause adverse effects in humans or other living organisms. Source
• Light pollution: Excessive or misdirected artificial light. Source
• Radioactive contamination: The deposition of radioactive substances on surfaces or within solids, liquids, or gases.
• Thermal pollution: The discharge of waste heat into the environment.
• Visual pollution: The negative aesthetic effects of signs, buildings, and other structures on the environment.

Pollution can have a wide range of negative impacts on human health, the environment, and the economy.