An air defense identification zone (ADIZ) is a region of airspace in which a country tries to identify, locate, and control aircraft in the interest of national security.[1] It is declared unilaterally[2] and may extend beyond a country's territory to give the country more time to respond to possibly hostile aircraft.[3] The concept of an ADIZ is not defined in any international treaty and is not recognized by any international body.[3][4]
The first ADIZ was established by the United States on December 27, 1950, shortly after President Truman had proclaimed a national emergency during the Korean War.[5] About 20 countries and regions now have such zones, including Canada, India,[6] Japan, Pakistan, Bangladesh, Finland, Norway, the United Kingdom, the People's Republic of China, South Korea, Taiwan, United States, Iceland, and Iran. As well, Russia and North Korea have unofficial zones.[1][3][7] Usually, such zones cover only undisputed territory, do not apply to foreign aircraft not intending to enter territorial airspace, and do not overlap.[4][8]
Air defense zones should not be confused with flight information regions (FIRs), which are used to manage air traffic.[1]