**2.2 Indoor residual spraying (IRS)**

Indoor residual spraying (IRS) consists of spraying a residual insecticide on the walls and other housing structures once or twice a year [1]. Mosquitoes and other insects that come into contact with these surfaces can be destroyed by the insecticide. Several pesticides have been used for IRS in the past, with DDT being the first and most well-known. Pyrethroids are also used in IRS, where they are sprayed on indoor surfaces.
