Chagos Archipelago sovereignty dispute
Sovereignty over the Chagos Archipelago has been disputed between Mauritius and the United Kingdom, which administers it as the British Indian Ocean Territory (BIOT). Mauritius has repeatedly claimed the Chagos Archipelago as part of its territory and that the British claim is a violation of United Nations resolutions banning the dismemberment of colonial territories before independence.
Source: Wikipedia — Chagos Archipelago sovereignty dispute (CC BY-SA 4.0)