Whether you will have to pay a penalty depends on the engine type of your vehicle and when your vehicle was registered. Cars must comply with the European Emissions standards. These are a set of EU wide regulations which define acceptable limits for exhaust emissions of new light duty vehicles in the EU and EEA member states. The Euro Emissions standards were first introduced in 1992, known as Euro 1. These regulations are designed to become more stringent over time, with the current standard—Euro 6—introduced in September 2015. However, as petrol and diesel have different emissions, they are subject to different standards.To comply with CAZ, petrol cars must have a Euro 4 approved engine, whereas diesel engines must be Euro 6 approved. Diesel vans sold since September 2016 comply with the Euro 6 emissions standards. Any vehicles with engines that predate these European emission standards will face penalties, depending on your local authority. However, if your vehicle meets the Euro 4 or Euro 6 emission standards or you have an electric vehicle, you will be exempt from any charges.Penalties and exemptions will differ across different cities. In London, the charges apply to all non-compliant vehicles in the ULEZ area. ULEZ will be enforced in April 2019 and will cover areas of central London—the same areas as the congestion charge zone. It will operate 24 hours a day, every day of the week. For cars, vans and motorcycles that have engines that are pre-Euro 6 and pre-Euro 4, the charge will be £12.50 a day. Drivers of buses, coaches and lorries will have to pay £100.However, in other cities such as Leeds, a £50 charge will apply to buses/coaches and HGVs that aren’t compliant. And private hire cars and taxis will pay £12.50. Private cars, light goods vehicles, vans, and motorcycles will not be charged.