DDT was used heavily worldwide in the 1950s and 1960s both in agricultural production and for malaria control. DDT has been widely banned because of it builds up in the food chain where it persists in fatty tissues of animals and humans (it can be monitored in human breastmilk), its ability to move from tropical to temperate zones where break down is further delayed, and its association with a number of chronic illnesses. For these reasons, many governments have banned DDT, and addressed its elimination over time in the Stockholm Convention on Persistent Organic Pollutants (POPs treaty).
The WHO malaria eradication program of the 1950s and 1960s helped to control malaria in many places, but wiping out malaria with DDT was an unrealistic goal. One of the many reasons for the failure of this ambitious effort was resistance to DDT among malaria-carrying mosquitoes. Taking into account that resistance arose largely from agricultural use and cross-resistance to pyrethroid insecticides, by 1972 nineteen species of mosquitoes were resistant to DDT in Africa. Resistance continues to be a problem.
Often DDT intended for indoor spraying to control mosquitos is diverted to illegal agricultural use, increasing the danger for human exposure and hastening the development of resistant mosquito populations.
New DDT use adds to exposure from old stockpiles that are not properly contained or controlled. The Food and Agriculture Organisation of the United Nations estimates there are more than 100,000 tons of obsolete pesticide stockpiles in Africa, mostly older chemicals such as DDT.
New demands for DDT use for malaria control also increase the burden on the communities living near production plants. A DDT factory in the Eloor-Edayar region in India has a long record of contaminating the environment, including rivers. The local community is now protesting their poisoning as a result of emissions from this factory.