Uber is adding a surcharge to its fares to help pay for cleaner vehicles.
The minicab app firm announced that all vehicles operating standard uberX journeys in London will be hybrid or fully electric by the end of 2019.
It is hoping to reach the same standard across the rest of the UK by 2022.
From next month, a 35p surcharge will be added to fares in London to help fund a scheme whereby Uber drivers can receive up to £5,000 towards the cost of upgrading their car to a hybrid or electric model.
A fee will also be added to journeys in other towns and cities over the next year.
Other measures being introduced by Uber include offering up to £1,500 of credit to 1,000 people scrapping an old diesel vehicle and a goal of making every Uber vehicle in London electric by 2025.
Fred Jones, Uber's head of UK cities, said: "Air pollution is a growing problem and we're determined to play our part in tackling it with this bold plan.
"Londoners already know many cars on our app are hybrids but we want to go much further and go all electric in the capital.
"Our scrappage scheme will also take polluting vehicles off the road and encourage Londoners to get into a shared car to connect with public transport instead."
Air pollution causes an estimated 40,000 premature deaths a year in the UK and is linked to a number of health problems including childhood illnesses, heart disease and dementia.
In July, the Government announced proposals to introduce a "targeted scrappage scheme" as part of its court-mandated plans for meeting legal European Union limits on harmful nitrogen dioxide pollution.
It would be focused on drivers who need most support, such as those on lower incomes or living next to a clean air zone.
Ministers also plan to ban the sale of all conventional diesel and petrol cars by 2040, and are considering funding measures to cut pollution with a tax on new diesel vehicles.
Alan Andrews, of environmental law firm ClientEarth, said: "To bring air pollution to within legal limits as soon as possible, we have to reduce emissions from road transport in our polluted town and city centres, and switching over to cleaner vehicles is part of this.
"The private sector is beginning to take positive steps in this direction, which should be welcomed, but this shouldn't let the Government off the hook."