London’s ultra low emission zone (ULEZ) – described by mayor Sadiq Khan as the world’s toughest vehicle emissions standard – began on Monday.

The Central London ULEZ will operate in the same area as the current Congestion Charge zone, but 24 hours a day, seven days a week.

Motorists who drive into the zone in a vehicle that does not meet the new emission standard (petrol vehicles that do not meet Euro 4 standards and diesel vehicles that do not meet Euro 6) will have to pay a daily charge on top of the Congestion Charge.

Mr Khan said: ‘This is a landmark day for our city. Our toxic air is an invisible killer responsible for one of the biggest national health emergencies of our generation. I simply refuse to be yet another politician who ignores it.

‘The ULEZ is the centrepiece of our plans to clean up London’s air – the boldest plans of any city on the planet, and the eyes of the world are on us.’

He added: ‘This is also about social justice - people in the most deprived parts of London, who are least likely to own a car, suffer the worst effects of harmful air pollution.’

The mayor’s office said that with polluting vehicles accounting for around 50% of London’s harmful Nitrogen Oxide emissions, the ULEZ ‘will help address London’s toxic air health crisis that currently leads to thousands of premature deaths annually, and increases the risk of asthma, cancer and dementia’.

It said that thousands of motorists have already started to change their behaviour ‘by driving less polluting vehicles into the area, and using cleaner transport alternatives including walking or cycling, and public transport'.

Since the Toxicity (‘T’) charge was introduced in February 2017 as forerunner to the ULEZ, there has been a 55% increase in the proportion of compliant vehicles in the Central London ULEZ zone, the mayor’s office said.

It added that a major awareness campaign has been underway for more than nine months to ensure drivers and businesses are ready for the ULEZ, with TfL’s online vehicle checker being used more than 3.2 million times during this period.

Polling shows 90% of drivers 'know something about the ULEZ scheme', the mayor’s office said.

However, the British Vehicle Rental and Leasing Association’s (BVRLA) chief executive, Gerry Keaney, said that while businesses across the capital are upgrading their fleets to comply with the ULEZ, ‘it is clear that many smaller firms are still unaware of the zone or are struggling to afford the switch to expensive new low emission vans and trucks’.

The BVLRA said that with the ULEZ set to be expanded in 2021, it is calling on Mr Khan, Transport for London and the Government to:

• Provide more money for ULEZ mitigation measures that can help fleets and individuals either upgrade their vehicles or make the shift into more sustainable modes of transport
• Ensure that future zero emission zones are properly signposted, managed and co-ordinated and give adequate consideration to the cost and supply constraints surrounding electric vehicles
• Focus on bottlenecks within London’s public EV charging network, ensuring priority access for commercial vehicle fleets and car share providers
• Embrace the behaviour change potential of Mobility Credits, which encourage people to abandon vehicle ownership in favour of a credit that can be used on public transport, bike and car sharing