A consultation on plans to expand London’s Ultra Low Emission Zone (Ulez) to cover the entire city has been launched.
Sadiq Khan, the capital’s mayor, is proposing to extend the scheme’s boundary from the North and South Circular Roads to the whole of Greater London from August 29 next year.
Drivers of vehicles which do not comply with minimum emissions standards are charged a daily fee of £12.50 for entering the Ulez.
The consultation is being conducted by Transport for London.
Analysis by the PA news agency found that more than 3.5 million more people will live within the Ulez if it is expanded as planned.
The mayor’s office estimated that an additional 135,000 vehicles would be affected per day.
It warned that the capital is suffering a “toxic air crisis”, with around 4,000 premature deaths in 2019 attributed to filthy air.
The boroughs of Barnet, Bromley, Croydon and Havering had the most deaths, demonstrating that poor air quality “is not just a central London problem”, according to Mr Khan’s office.
Whether or not a vehicle is liable for the Ulez charge depends on how much nitrogen dioxide (NO2) it emits.
NO2 damages lungs and can exacerbate existing conditions such as asthma and lung and heart disease.
For diesel cars to avoid the charge they must generally have been registered after September 2015, while most petrol models registered from 2005 are exempt.
Mr Khan previously ruled out introducing a Clean Air Charge, which would have affected drivers of all but the cleanest vehicles.
He also decided not to go ahead with a proposal to charge drivers of vehicles registered outside London for entering the capital.