The three zone classes
Zone 1, applies to heavy lorries and buses. They must meet a Euro standard set in the local traffic regulation for that place. In force in several cities, and the oldest of the three: this class has existed since 1996. Zone 2, reaches ordinary cars and light vehicles as well. Petrol and gas vehicles must meet at least Euro 5, diesel vehicles Euro 6, and heavy vehicles Euro VI. Zone 3, the strictest. Only electric vehicles, fuel-cell (hydrogen) vehicles, and gas vehicles meeting Euro 6 may drive there. Heavy lorries and buses may additionally be plug-in hybrids if they meet Euro VI, but a plug-in hybrid car is not allowed, whatever its electric range. Classes 2 and 3 have been available to municipalities since 2020. No Swedish city has a class 3 zone in force: Stockholm decided on one for part of the inner city, and the county administrative board set that decision aside in 2025. Which class applies, and to which streets, is a local decision. It is shown by signs and set out in the municipality's local traffic regulations, always read the sign and any plate beneath it.