Diesel became Europe's most expensive fuel at the pump on Sept. 21, when the EU weighted average reached a record €2.226 per litre, according to the European Commission's Weekly Oil Bulletin. The price was 13.4 cents above Euro-super 95 petrol and has risen about 40% since late February as the war with Iran disrupted energy flows through the Strait of Hormuz. A 50-litre diesel tank now costs about €111, with taxes accounting for 38.6%, or €0.861 per litre. Refining margins contributed €0.41 per litre in the third week of September, European Central Bank experts estimated. Diesel remains more lightly taxed than petrol under EU minimum-duty rules, although a proposed shift to energy-based taxation failed to secure unanimous support in November 2025. The article also details diesel taxes and pump prices in the 10 EU countries with the highest per-litre tax burdens, while Germany, Czechia and Spain have announced or extended relief measures as governments respond to record fuel costs.