IDANT 2025: Leaders in Vienna, New York reaffirm support for nuclear test ban

Every year on 29 August, the world marks the International Day Against Nuclear Tests (IDANT) - a United Nations-designated day dedicated to ending nuclear test explosions worldwide.  

In 2025, the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) commemorated IDANT with events in Vienna and New York that brought together diplomats, international officials, and students to remember the devastating legacy of past nuclear tests and to reaffirm the global commitment to a nuclear test-free world. These observances highlighted both the progress made towards ending nuclear testing and the urgent steps still needed to bring the Comprehensive Nuclear-Test-Ban Treaty (CTBT) into force. 

Established by the UN General Assembly in 2009 at the initiative of Kazakhstan, IDANT marks the date in 1991 when the country closed the Semipalatinsk nuclear test site, one of the world’s major testing grounds. 

Today, 187 countries have signed and 178 have ratified the CTBT; however the Treaty cannot enter into force until the remaining nine required States ratify it. Speakers in Vienna and New York urged them to join the Treaty without further delay. 

On 29 August, the CTBTO hosted an event at the Vienna International Centre (VIC) to mark the International Day Against Nuclear Tests. The event brought together representatives from Permanent Missions in Vienna, staff from international organizations, and a group of secondary school students from local international schools’ Model United Nations programmes.  

The programme included statements from senior officials, beginning with a video address by Philemon Yang, President of the 79th session of the UN General Assembly. In his remarks, he emphasised “We must act with urgency to achieve our shared goal, a world free of nuclear weapons. This is not an abstract ambition. It is a matter of survival for present and future generations alike.” 

Following the video message, CTBTO Executive Secretary Robert Floyd delivered remarks in person, along with Ambassador Mukhtar Tileuberdi, Kazakhstan’s Permanent Representative in Vienna, Rebecca Jovin, Chief of the UN Office for Disarmament Affairs (Vienna Office), and a representative of the CTBTO Youth Group (CYG), Chiara Cogliati. Each speaker brought their unique perspectives, highlighting the ongoing work and collective efforts to prevent nuclear testing around the world. 

Floyd addressed the young participants, saying: “The world has changed dramatically. In my youth, we witnessed more than 1,000 nuclear tests. In yours, fewer than 10. And at the CTBTO, we have one clear goal, which we reaffirm on this International Day Against Nuclear Tests: to celebrate each passing year without a single test.” 

Ambassador Tileuberdi reflected on Kazakhstan’s historical role as the site of Soviet nuclear testing and its leadership in initiating IDANT: “I take this opportunity to call on each of you to support our shared goal– the universal, legally binding prohibition of nuclear testing – and to join all UN-led disarmament initiatives aimed at building a safer, more secure, and nuclear-weapon-free world. Let us remain united in this noble cause.” 

Rebecca Jovin framed the day’s importance succinctly: “This year’s commemoration reminds us not only of the devastating and catastrophic legacy of nuclear testing, but also of our collective responsibility to ensure such history is never repeated.” 

On 3 and 4 September, the United Nations General Assembly (UNGA) held its annual high-level observance of the International Day Against Nuclear Tests at UN Headquarters in New York. Delegations from around the world, including ministers and ambassadors from CTBT State Signatories, came together to reaffirm their support for a permanent end to nuclear testing.  

Convened by the President of the General Assembly, the meeting featured a series of national statements that celebrated the global norm against nuclear testing and called for stronger collective action to finally make that norm legally binding.  

Representatives of States Signatories took the floor one by one, each expressing their countries’ commitment to upholding the moratorium on nuclear testing. From longstanding supporters of the CTBT to more recent signatories, the message was clear: In an era of growing global tensions, reaffirming the global ban on nuclear testing is more critical than ever.   

Ambassador Ricklef Beutin, Permanent Representative of Germany to the United Nations, speaking on behalf of the Group of Friends of the CTBT, put it this way: “We can say with confidence that the CTBT stands as one of the clearest demonstrations of what international cooperation can achieve. It is a core element of the international nuclear non-proliferation and disarmament regime.” 

And looking ahead to the upcoming Article XIV Conference, Chargé d’Affaires and Ambassador Leila C. Lora-Santos, Deputy Permanent Representative of the Philippines, underscored the point: “We call on all delegations to seize this opportunity to reaffirm collective support for the CTBT and to work together in advancing practical actions that can bring the Treaty into force and strengthen the global norm against nuclear testing.” 

As the events in Vienna and New York came to a close, one message stood out: a renewed commitment to a world free of nuclear testing. From diplomats to young advocates, the international community came together to reaffirm that nuclear testing is part of the past, not the future. The collective will is stronger than ever, and a nuclear-test-free world is not just achievable, it is essential for the future.