Earlier quoted context omitted.
This BBC article does a really poor job of explaining the context of this situation or why fuel would be so much cheaper in Slovenia, so I had to look around. Slovenia apparently introduced fuel price regulations last year (for motorway service stations; off-motorway stations have been regulated for longer), as a means of reducing costs for consumers[0]. These price caps were, in fact, removed a week ago[1], and pric…
In Slovenia, fuel prices have been regulated since, like, forever. A few years ago (or last year? not sure) they were deregulated on the highways (i.e. to make tourists pay more) but then the government changed their mind (several times, IIRC).
Somewhere in between, a feud started between the largest provider Petrol and govt, and govt started regulating the highway prices too for no good reason.