The 2026 conflict severely disrupted shipping through the Strait of Hormuz, a route that carried an average of 20 million barrels of oil and oil products per day in 2025. On March 11, the International Energy Agency said crude and refined-product exports through the strait had fallen to less than 10% of prewar levels.
Why the disruption mattered
The IEA estimated that Hormuz carried about a quarter of global seaborne oil trade in 2025 and said there were limited routes to bypass it. The disruption forced producers to curtail output and tightened markets for fuel products, including diesel, jet fuel and liquefied petroleum gas. The IEA later described tanker movements as near a halt and said restoring transit was necessary to return stable oil and gas flows.
On March 11, the 32 IEA member countries unanimously agreed to make 400 million barrels from emergency reserves available to the market. The agreement authorized stock availability over schedules set by each country; it did not mean all barrels were immediately released. This was the largest coordinated stock release in the agency's history.
The IEA's export measure tracks oil volumes through Hormuz. The sharp fall in exports and the coordinated reserve release show the scale of the supply disruption.
For the military chronology, see why the war began; for Iran's regional attacks, see missiles and air defense.
The IEA documented the export disruption and the 400-million-barrel emergency stock decision. Its later report explains market impacts and the importance of reopening the strait. The U.S. Energy Information Administration's October outlook tracks oil-flow constraints and resulting market volatility.