May 20, 2026 [Reuters]- Chinese ​state refiners have slashed oil throughput by more than one million barrels per day since the outbreak ‌of the Iran war, analysts and market sources said, as disruption to crude supplies and poor margins forced them to scale back operations.

The drop in output by oil majors Sinopec, PetroChina, CNOOC and Sinochem, which account for about 60% of China’s refining capacity, has weakened crude demand ​from the world’s top importer and could tighten domestic fuel supplies.

Chinese state refiners are processing 8.4 million barrels per ​day of crude this month, down from 8.6 million bpd in April and 9.5 million bpd ⁠in March, according to consultancy Energy Aspects, compared with about 10 million bpd before the U.S. and Israel attacked Iran ​at the end of February.

Chinese research firm Horizon Insights expects throughput for state refiners to fall to 8.35 million bpd in ​May, down from 8.61 million bpd in April and 10.17 million bpd before the conflict began, based on its data.

The refiners, which depend heavily on Middle Eastern crude, started lowering rates in March, while independent refiners in the industry hub of Shandong province only began cutting output this ​month as margins crumbled.

Surging oil prices and weak fuel demand caused refining margins for state refiners to collapse to about 3,200 ​yuan ($470.71) per metric ton in late April, Horizon data showed, although losses have since narrowed to around 300 yuan per ton.

SINOPEC BRINGS FORWARD ‌MAINTENANCE

As ⁠a result, Sinopec brought forward maintenance at two refineries, Yangzi Petrochemical and Hainan Petrochemical, to May and July, respectively, from the fourth quarter, four trade sources familiar with the matter said. The refineries combined can process more than 400,000 bpd of crude.

Sinopec did not immediately respond to a request for comment.

The world’s largest refiner has also sharply cut crude loadings from Saudi Arabia ​in May amid high prices, ​and does not plan to ⁠load any Saudi cargo in June, trade sources said.

China’s total crude throughput in April fell to 13.3 million bpd, its lowest since August 2022, official data showed on Monday.

Energy Aspects expects China’s overall ​May throughput to fall to 13 million bpd due to the run cuts.

FUEL STOCKS AND ​EXPORTS

Despite run cuts, ⁠China’s refined products inventories have risen since April after Beijing imposed curbs on exports in mid-March, multiple industry sources said.

Since March, commercial inventories of diesel and gasoline have risen above 2025 average levels, according to local consultancy OilChem.

April exports of diesel, gasoline and jet fuel ⁠totalled 1.24 ​million metric tons, customs data showed, the lowest since February 2015.

Industry estimates ​put May exports at about 500,000 tons, excluding shipments to Hong Kong.

Exports are expected to remain subdued in the coming months due to the government curbs, two ​of the sources said.