Used primarily as a pesticide in agricultural and public health programs to control insects such as mosquitoes, flies, and lice. It has been widely applied in malaria control efforts by reducing mosquito populations that transmit the disease. Also used in some cases for controlling insect pests in crops and livestock, though its use has declined significantly due to environmental persistence and toxicity concerns. Restricted or banned in many countries because of adverse effects on wildlife, particularly birds, and potential human health risks.