The legality of the Air Defence Identification Zones under International Law

Abstract

Air Defence Identification Zones are unilaterally declared designated areas of nonterritorial airspace where states impose reporting obligations on civil and military aircraft for the purpose of national security.1 The purpose for ADIZ is said to be national security; however some argue that ADIZs are used as a ploy by states to extend their territory and in doing so violate international air law by restricting the freedom of overflight in international airspace.2 However this cannot be argued at face value, simply because there is no universal procedure for the adoption of ADIZ, leaving the implementation of ADIZ rules open to varied practice by states. The United States and China are used as case studies to show the varied practice of ADIZ by states and the cause of such misconception. One major difference is the threat of the use of force in the East China Sea ADIZ for non-compliance with China’s ADIZ rules. This is a clear violation of international law as international airspace is free for all and no state can claim exclusive jurisdiction over it. The legality of ADIZ is the main concern of this thesis and different sources of international law will be discussed with an aim to conclude the legality of ADIZ.