UN Secretary-General Ban Ki-moon on Wednesday stressed the importance of a global ban on nuclear tests to achieve a safer and more secure world, calling on all States that have not yet done so to sign and ratify the international treaty that seeks to achieve this goal. “Nuclear tests remain a threat to human health and global stability,” Ban said in his message for the third annual International Day against Nuclear Tests, observed on 29 August. The Day highlights the efforts of the UN and a growing community of advocates, including Member States, intergovernmental and non-governmental organizations, academic institutions, youth networks and media in informing and educating on the importance of the nuclear-test-ban. The General Assembly chose 29 August as the annual commemoration date since it marks the day in 1991 when Semipalatinsk, one of the largest test sites in the world and located in north-eastern Kazakhstan, was closed for good. The UN Chief noted that the Day is an important opportunity to call attention to the harmful and long-lasting effects of testing, as well as the continued danger posed by the existence of tens of thousands of nuclear weapons. “Around the world, symposia, conferences, exhibitions and competitions are being held to raise public awareness and galvanize action to finally end nuclear tests,” he stated. “To achieve this goal, States that have not yet signed and ratified the Comprehensive Nuclear-Test-Ban Treaty (CTBT) must do so without delay.”