Lead- and sulphur-free petrol is intended primarily for vehicles equipped with catalyzers to reduce emissions.  This fuel should not be used for aviation. The products are normally referred to as "Unleaded 95" and "Unleaded 98".
An exceptionally low sulphur content in petrol improves the effectiveness and lifespan of catalytic converters in both older and new vehicles.  Gasoline with minimal sulphur content also reduces toxic emissions which in turn leads to a better level of efficiency. 10ppm Gasoline is suitable for all vehicles but especially in connection with new, eco-friendly vehicle technology such as Denox catalyzers that are primarily used in engines with direct injection.

By running on almost sulphur-free fuel, the direct-injection systems can fulfil the potential for lowering consumption and therefore reducing CO2 emissions.

Petrol with a sulphur content of 10 parts per million is classified as "sulphur-free".