The document discusses various types of pollution including air pollution. It defines pollution as the introduction of substances that cause adverse environmental changes. Air pollution is defined as the release of pollutants such as gases, particles, and biological molecules into the air which are harmful to human health and the environment. Some common air pollutants are emitted from sources like vehicle emissions, industrial effluence, and biomass burning. The document further discusses the causes, effects, and examples of air pollution as well as prevention methods.