The United Nations Relief and Rehabilitation Administration (UNRRA) was an international agency which coordinated measures for the relief of victims of war in any area under the control of any of the United Nations. Given the prominent presence of malaria in Greece, UNRRA contracted with the Tennessee Valley Authority (TVA) to convert ten biplanes for malaria control purposes. TVA equipped the planes with DDT thermal aerosol devices and trained one of the UNRRA pilots in the techniques of DDT application from the air.