Where is the Strait of Hormuz? What is it, will Iran close it as US asks China to stop country from closing route - what will happen if Iran does

The Strait of Hormuz is one of the world's most important shipping routes. Over a fifth of the world’s oil supply, 20m barrels, and much of its liquified gas, passes through the route each day.

Iran has in the past threatened to close the strait, which would restrict trade and impact global oil prices, but has never followed through on the threat. The Strait of Hormuz is geo-strategically important to the United States and beyond, as the strength of the global economy is heavily dependent on the flow of oil.

The strait lies between Oman and Iran and links the Gulf to the north with the Gulf of Oman to the south and the Arabian Sea beyond. It is 33km wide at its narrowest point, with the shipping lane just 3km wide.

Between the start of 2022 and last month, approximately 17.8 million to 20.8m barrels of crude, condensate, and fuels flowed through the strait daily, according to data from analytics firm Vortexa. Members of the Organization of the Petroleum Exporting Countries (OPEC) – Saudi Arabia, Iran, the United Arab Emirates, Kuwait and Iraq – export most of their crude via the strait, mainly to Asia.

The US Fifth Fleet, based in Bahrain, is tasked with protecting commercial shipping in the area. Closing the strait would trigger an oil price spike with a near immediate inflationary effect in the US and across the globe.

In particular, closing the strait would significantly harm China. The world’s second-largest economy buys almost 90% of Iran’s oil exports, which are subject to international sanctions.

US secretary of state Marco Rubio has called on China to help stop Iran from closing it, telling Fox news: “I encourage the Chinese government in Beijing to call them about that, because they heavily depend on the strait of Hormuz for their oil If they do that, it will be another terrible mistake. It’s economic suicide for them if they do it.”

Closing it would also be an act of dramatic economic self-harm. Iranian oil uses the same gateway, and shutting Hormuz risks bringing Gulf Arab states, who have been highly critical of the Israeli attack, into the war to safeguard their own interests.