<prompt> The distance from airpo or seapo which has to be free from mosquitoes is -400 m500 m1 km100m  <response>: - The aircraft and ships arriving from endemic areas are subjected to aerosol spraying with prescribed insecticides on arrival for destruction of insect vectors. -The distance from airpo or seapo which has to be free from mosquitoes is 400 meters. Reference : Parks textbook of preventive and social medicine, 23rd edition pg no:284 