The congestion charge for people driving into central London has now increased by 30 per cent.
Expected to be in place for a year, the charge has risen from £11.50 to £15 and will now be enforced everyday from 07:00-22:00.
It is one of the conditions of a recent £1.6bn bailout deal between Transport for London and the government.
However, the emergency services, NHS and care workers will still have the charge reimbursed.
Residents applying for a discount have until 1 August to submit their applications.
TfL said data showed the number of cars in the zone was the same as before lockdown began in March.
It said as the government further eased lockdown restrictions, traffic levels could double if people who would have used public transport chose to drive instead.
This would mean there would not be enough space on the streets to accommodate the increased amount of walking and cycling needed in order to enable people to socially distance, TfL said.