Sri Lanka ratifies CTBT, propelling South Asia towards full adherence to Treaty

Sri Lanka has become the 178th state to ratify the Comprehensive Nuclear-Test-Ban Treaty (CTBT). This milestone moves South Asia closer to achieving full adherence to the Treaty and was commemorated with a ceremony at the United Nations Headquarters in New York.

The event was attended by Mohan Pieris, the Permanent Representative of Sri Lanka to the United Nations, and Andrei Kolomoets, Officer-in-Charge of the Treaty Section of the UN Office of Legal Affairs (UNOLA).

Sri Lanka's ratification of the CTBT comes after the Cabinet of Ministers officially approved the Treaty on 6 June, following a visit from Robert Floyd, the Executive Secretary of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO).

“This development demonstrates the power of together, advancing the global momentum towards a world free from nuclear testing,” said Floyd. He emphasised that the cause strongly resonates with the Sri Lankan people.

The CTBTO head also expressed gratitude to President Ranil Wickremesinghe, whom he met during his official trip, and all the authorities who played vital roles in the process. Special mention was made of Foreign Minister Ali Sabry, Foreign Secretary Aruni Wijewardane, and Majintha Jayesinghe, the Permanent Representative of Sri Lanka to the United Nations in Vienna.

During his visit to Colombo last month, Floyd also held meetings with Environment Minister Naseer Ahamed, General Kamal Gunaratne, Secretary of the Ministry of Defence, and Ravirajasinghe Sanjeepan, the Chairman of the Geological Survey and Mines Bureau (GSMB) of Sri Lanka.

The GSMB serves as the National Data Centre (NDC), acting as the focal point for data transmission between the CTBTO's International Data Centre (IDC) and Sri Lanka’s authorities.

Notably, Sri Lanka was among the first signatories of the CTBT in October 1996, just days after the Treaty opened for signature. The country is already a State Party to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), the Biological Weapons Convention (BWC), and the Chemical Weapons Convention (CWC).

“The best way to uphold the norm against testing is to reaffirm and enhance support for the CTBT – to reinforce its existing strengths and to strive to bring about its entry into force,” said Izumi Nakamitsu, UN Under-Secretary-General and High Representative for Disarmament Affairs.


The CTBT bans all nuclear test explosions everywhere, by everyone, and for all time. Adherence to the Treaty is nearly universal, with 186 State Signatories and 178 ratifying states. However, to enter into force, the Treaty must be ratified by all 44 States listed in its Annex 2, for which eight ratifications are still required.
The CTBTO has established an International Monitoring System (IMS) to ensure that no nuclear explosion goes undetected. Currently, 305 certified facilities – of a total of 337 when complete – are operating around the world. The data collected by the IMS serves multiple purposes, including disaster mitigation, such as earthquake monitoring and tsunami warning. Additionally, it supports research in various fields, ranging from whale migration, climate change studies, to predicting monsoon rains.

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La Neice Collins
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