Press Release – CTBTO The Union of the Comoros has become the 170th state to ratify the Comprehensive Nuclear-Test-Ban Treaty (CTBT), bringing the Treaty yet another step closer to universal recognition and marking a fresh milestone on the road to end nuclear testing for … The Union of the Comoros has become the 170th state to ratify the Comprehensive Nuclear-Test-Ban Treaty (CTBT), bringing the Treaty yet another step closer to universal recognition and marking a fresh milestone on the road to end nuclear testing for all time. The Indian Ocean nation – one of 185 countries that have signed the CTBT – deposited its instrument of ratification with the United Nations Secretary-General in New York on 19 February 2021.