World Cleanup Day

World Cleanup Day is a global social action program aimed at combating the global solid waste problem, including the problem of marine debris. It is held annually on 20 September, and is coordinated by the global organization Let's Do It! World, whose headquarters are located in Tallinn, Estonia.

World Cleanup Day includes litter cleanup and waste mapping activities spanning every time zone. Environmental cleanup events are held in nearly every country until concluding near the international date line in Hawaii and American Samoa. From 2024, World Cleanup Day has been declared an official UN holiday, and added to the official UN calendar of days and weeks.