The system of four labels — Zero Emissions, ECO, C and B – will stay, but the criteria are being redefined. The DGT says the new rules will give a more accurate picture of how much pollution each vehicle really produces. C: Petrol vehicles that comply with Euro 6d and diesel vehicles meeting Euro 6d-TEMP or Euro 6d. B: Older petrol cars (Euro 4) and diesel vehicles (Euro 6) that don’t fit the higher groups. If you’re considering changing cars, keep the 2026 rules in mind, otherwise you might end up buying something that’s already outdated by the time the new labels kick in.