North Korea raised alarm bells in January with claims it had successfully tested a hydrogen bomb.

On Tuesday, scientists behind the world's "Doomsday Clock" announced it would remain at three minutes to midnight, saying the decision "is not good news". The clock is a metaphor for how close the world is to catastrophe owing to climate change and nuclear weapons. 

So how worried should the world be about the prospect of nuclear war? In the Headliner, Mehdi Hasan speaks to Hans Blix, the former head of the International Atomic Energy Authority. 

Blix also discusses the Iran deal and how much the US-led invasion of Iraq caused the creation of ISIL. 

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Source: Al Jazeera