A demilitarised buffer zone (DMZ) is an international concept and institution, defined as a designated geographical area where military forces, operations, and installations are prohibited or restricted by formal agreement between nations. The concept emerged prominently after World War I, with an early example being the demilitarisation of the Rhineland following the Treaty of Versailles (1919), and became a key instrument during the Cold War to manage tensions between opposing ideological blocs. The primary problem it solves is reducing the likelihood of direct military conflict by creating a physical separation between hostile forces.
The mechanism works through a mutual agreement, such as a peace treaty or armistice, which establishes a clearly defined geographical area where the prohibition of military personnel and equipment is enforced. Key provisions typically require the evacuation of all combatants, mobile weapons, and military equipment, and prohibit any hostile use of fixed military installations or any activity linked to the military effort. Enforcement may involve international oversight, such as the Multinational Force and Observers (MFO) in the Sinai Peninsula, established after the 1979 Egypt–Israel Peace Treaty.
The concept connects to related institutions like the Korean Demilitarised Zone, a 4 km-wide buffer strip established in 1953 by the Korean Armistice Agreement between North and South Korea. Recently, the term has been applied to the India-China border along the Line of Actual Control (LAC) in Eastern Ladakh. Following the June 2020 Galwan Valley clash, demilitarised buffer zones were created at friction points like Galwan River Valley, Hot Springs (PP 15), and Gogra (PP 17A) as part of disengagement agreements between February 2021 and September 2022. This change has replaced the traditional Patrolling Points (PPs) system in those areas, altering the LAC profile and restricting India's access to some traditional patrolling points and grazing lands.