CTBT stands for Comprehensive Nuclear Test Ban Treaty. It is a multilateral treaty that bans all nuclear test explosions and other nuclear explosions for civilian or military purposes. The treaty was adopted by the United Nations General Assembly and it was opened for signature on 24 September 1996. The treaty is signed by 182 countries. As of 2016, Trinidad and Tobago is the last nation to sign the treaty.
It acts as a barrier to the development of nuclear weapons. It does not allow the development of new nuclear weapons and any improvement in the existing nuclear weapons. It is a legal binding norm against nuclear testing. It prevents human suffering and damages to the environment due to nuclear explosions.
Over 2000 nuclear tests were conducted by different countries between 1945 and 1996, before the CTBT was adopted:
After 1996, three countries conducted nuclear tests: India and Pakistan in 1998, the North Korea in 2006 and 2009.
The treaty has not entered into force yet as there are 44 countries who didn't sign and ratify the treaty. As of August 2011, 35 of these 44 countries have ratified the treaty. The nine countries who did not ratify it are India, Iran, Israel, Pakistan, China, Egypt, Indonesia, the United States and the North Korea. Out of these nine countries, India, Pakistan and North Korea have not yet signed it.
If a country Signs the treaty, it means, the country accepts the treaty and it will not take any action against the purposes of the treaty. It is signed by the senior representative of a country such as president, prime minister, foreign minister etc.
If a country ratifies the treaty, it means, it is officially sanctioned to make it a legally binding for the government of the country. In this process, the treaty is adopted by the Legislature of the country such as the Parliament. Then the instrument of ratification is submitted to the UN Secretary-General.