Around 1,700 fines have been issued to passengers caught without a face covering on London’s public transport network.
Transport for London (TfL), which released the figure, said a further 2,100 people were ejected from services, with 9,300 prevented from boarding.
Some 128,000 people were told they could not travel unless they put on a face covering.
It has been mandatory to wear a face covering on public transport in England since June 15, in a bid to tackle the spread of coronavirus.
TfL initially focused on encouraging compliance, but switched to an “enforcement phase” on July 4.
Fixed penalty notices start at £200 for a first offence, and double for every subsequent offence up to £6,400.
TfL also has the option of launching prosecutions against people caught breaking the rules.
Around 650 people have been prosecuted, resulting in fines of up to £660 for first time offenders. One repeat offender is having to pay £1,170.
TfL’s team of enforcement officers now stands at around 500 after a further 20 personnel completed training last month.
The transport body said around three out of four passengers are supportive of face covering enforcement.
Director of compliance, policing operations and security Siwan Hayward said: “People should only be travelling if they have a legitimate reason and ensuring the network is safe for those customers, which include NHS and other key workers, is our top priority.
“Wearing face coverings, unless exempt, has been mandatory for seven months now and we continue to communicate the requirement in stations, on platforms and onboard services, so there really is no excuse for not wearing one properly for your entire journey when travelling on our network.
“London is at a critical point in this pandemic and this is no time to be complacent with the measures we take to protect ourselves and others.
“I want to thank all our staff for their hard work throughout the pandemic, including our enforcement team who have been doing an excellent job.”
Superintendent Gary Taylor from the roads and transport policing command at the Metropolitan Police said: “We are almost a year into living with this virus and by now everyone should know how to protect themselves and those around them.
“Wearing a face covering on public transport is just one of the ways to stay safe.
“Alongside our Transport for London partners, my officers will be out across London making sure those who use public transport are wearing a face covering.
“If officers on patrol see someone who isn’t complying with the rules, unless that person is exempt, they can expect to receive a fixed penalty notice.”