Three oil supertankers sail through the Strait of Hormuz

Two Chinese supertankers loaded with crude sailed through the Strait of Hormuz hours after a Greek vessel moved through the waterway, marking a significant uptick in oil shipping traffic days after a fragile ceasefire between the US and Iran was announced.

It represents the biggest day of oil exits through Hormuz since the war caused traffic through the waterway to all but halt six weeks ago. None are carrying oil from the Islamic Republic or have obvious, direct links to the country.

The reopening of Hormuz is critical to the world’s oil trade because its closure has resulted in the loss of millions of barrels of supply to global markets. A resumption would alleviate pressure on increasingly tight physical markets everywhere. The US and Iran are set to hold peace talks in Islamabad in the coming days.

The two Chinese supertankers are the first from the Asian nation observed taking barrels out of Persian Gulf, a boon for Beijing but nevertheless underscoring that the country has also been squeezed by the conflict.

In oil-flow terms, the exits are significant but still way below peace-time levels. 

The three tankers between them have a transport capacity of about 6 million barrels of crude. In addition, Iran, the only country really sending barrels through, exported at a rate of about 1.7 million barrels a day last month. That would imply roughly half the normal rate of shipments through the waterway — and only on a single day.

There’s also a third Chinese tanker, the Yuan Hua Hu, which hasn’t been signaling on Saturday, that had been waiting close by the first two before they moved to depart the Persian Gulf. 

The Greek tanker was signaling for Malacca in Malaysia, whose media reported on Friday a permission for the country’s freighters to depart. Malacca is also a waypoint for ships going elsewhere in Asia. Iran has said that vessels are allowed to sail through the waterway, but that they must get permission to do so.

The two Chinese supertankers are the Cospearl Lake and the He Rong Hai. The Greek one is the Serifos. Calls to the ships’ operators outside normal working hours either weren’t answered or weren’t immediately returned. The Serifos and the He Rong Hai loaded their cargoes in Saudi Arabia, while the Cospearl Lake did so in Iraq, the tracking data show.

All three appear to have followed a northerly route through the strait that has been demanded by Tehran. That path passes through Iranian waters and along the coasts of Qeshm and Larak Islands and is well away from the traditional Hormuz shipping lanes that hug the southern coast of the waterway.

Almost all traffic through the waterway, which normally handles about a fifth of the world’s oil and a similar portion of liquefied natural gas, ground to a halt within a day of the war starting on Feb. 28. 

While digital ship-tracking can be subject to manipulation, the three ships’ signals look consistent with genuine vessel movements.

This story was originally featured on Fortune.com