Iran shuts down the Strait of Hormuz. What more can it do?

Iran has declared the Strait of Hormuz closed and threatened to fire at any ship passing through it.  The narrow waterway is a vital chokepoint for global oil and gas, but also for other commodities such as fertiliser. France 24’s Yuka Royer speaks with Noam Raydan, a maritime risk expert at the Washington Institute for Near East Policy about the potential impact of the Strait’s closure and how Iran could further escalate the situation.