Middle Eastern oil producers are raising the export prices for their lower-grade crudes, Bloomberg reported earlier this week. And European buyers have no choice but to pay up—because the alternative is Russian oil, and they can’t have that.

It is a curious case, as noted in another Bloomberg report on the issue, since normally, the lower the crude grade, the lower the price. Light, sweet crudes like WTI or Arab Super Light fetch higher prices from refiners because they are easier to process into fuels.

Heavier crudes and crudes with higher sulfur content—sour crudes—are normally cheaper because their refining is a more complicated affair. Yet the refining business doesn’t follow this unshakeable logic. Refineries are calibrated to operate with certain types of oil, and a lot of European refineries were calibrated to operate with Russian Urals—a medium sour grade.

Energy Intelligence sounded the alarm as early as last year in an article that noted that European refineries had for decades processed Urals and would have a hard time replacing it with similar crudes. Global markets were amply supplied with light sweet crudes, the report pointed out, but the supply of medium sour ones was tighter.

A year later, it still is, according to the Bloomberg reports. And producers are responding the way sellers always respond when demand for their product surges. Iraq has raised the price of its Basrah Medium for European buyers to the highest in a year. Saudi Arabia also raised the price of its Arab Light, which is in fact a medium sour crude.

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At the same time, in what would probably seem like a cruel move to Europeans, both Iraq and Saudi Arabia kept their prices unchanged for Asian buyers—who, to be fair, normally buy a lot more oil than European refiners, and now they’re also gobbling up Russian barrels, making it unwise for the Iraqis and the Saudis to raise prices to them.

In addition to the replacement game that’s going on in international oil, there is also another factor: new refineries are coming on stream in the Middle East, so local consumption of various crudes is on the rise, leaving more limited volumes for export, as Bloomberg noted in a report that said the price changes in medium sour were taking traders by surprise.

Some relief for European refiners came from the U.S., whose oil exports to Europe were set to reach a record in March at around 2 million barrels daily, but the fact is that U.S. oil production consists mostly of light, sweet crudes that can’t replace Urals at European refineries.

They can’t replace heavy crudes for U.S. refineries, either, hence the United States’ continued dependence on imports of oil even after it became the world’s largest producer of the commodity.

This means that the market of medium sour crude grades is set for an extended period of tight supply. Until some producers decide to boost output, but they have little motivation to do it, what with the EU’s and the UK’s plans for phasing out fossil fuel consumption. With such a context for future demand, producers are unlikely to invest in a production boost.

This, in turn, means fuels will be more expensive for Europeans, and that would add fuel to already high inflation. A decline in benchmark oil prices would be a welcome respite but only a temporary one. Until refiners depend on imported sour crude from producer countries that make most of their money from their oil exports, they would be made to pay as much as the producers see fit.

India and China, meanwhile, have access to discount Russian crude—all grades—and cheap Middle Eastern crude, benefiting from both Europe’s questionable international policies and from internal competition in OPEC+. The EU might want to hurry up with replacing GDP with something else before the differences between its own GDP and China’s and India’s become too glaring.