Although it's one of the world's largest producers of crude oil, Russia is facing something that sounds almost impossible: empty petrol stations and kilometre-long queues, in which citizens wait up to 36 hours for petrol.

The cause is a series of Ukrainian drone attacks on Russian refineries. The damage is so serious that domestic fuel production no longer meets demand, so Moscow is seeking petrol from abroad - from Belarus and India. From an oil exporter, Russia has turned into a country urgently hunting for fuel.

The story is instructive for anyone who thinks military might means invulnerability too. Drones, relatively cheap compared to everything else in a war, proved enough to strike the lifeblood of an entire economy. When the refineries burn, it isn't the front that suffers - it's the ordinary driver who waits for hours at the pump, and the ratings of the authorities who promised stability.

For a reader in the Balkans, this carries a broader message too. The war in Ukraine has long since not been only their business - it hits fuel prices, energy markets and the nerves of all of Europe, us included. When a major oil producer has no petrol for its own citizens, that's a sign of how fragile the system we all rely on is, even those who think they're far from the front.