DDT (dichlorodiphenyltrichloroethane) is a pesticide that was widely used in the mid-20th century to control insects, particularly mosquitoes, which spread malaria and other diseases. However, it was later discovered that DDT was highly toxic to both humans and the environment. It caused a variety of health problems, including cancer, and it also had harmful effects on wildlife, particularly birds, by thinning their eggshells. Due to its toxic effects, DDT was banned for use in the United States in 1972 and in many other countries. It is not a product that can be legally produced, sold, or used in most parts of the world and it is considered as a persistent organic pollutant.