Vehicles that don’t meet certain emissions standards are now being hit with a £10 ($13.18) daily charge. The move is intended to reduce air pollution in one of Europe’s largest cities.

The “toxicity charge,” or “T-charge” as it’s known locally, is part of London Mayor Sadiq Khan’s plan to make inner London a zero emissions city by 2040. It primarily affects vehicles more than 11 years old.The new levy is in addition to the £11.50 ($15) congestion charge that all vehicles in the heart of the British capital need to pay between 7 a.m. and 6 p.m. That makes the total fee for some cars entering central London a whopping £21.50 ($28.41).

“I refuse to stand by while Londoners are killed by pollution,” Khan wrote in a comment piece published on Monday in London’s Evening Standard newspaper. “So I am implementing the most ambitious clean-air strategy of any city in the world to produce real results.”