Sadiq Khan is expected to discuss the Ulez expansion with other world mayors when he attends a major climate change summit in New York.
The mayor, accompanied by five aides, is due to fly to the US on Sunday to attend the United Nations General Assembly and take part in the UN climate ambition summit.
He is also expected to appear alongside Prince William at an Earthshot Prize summit, which awards prizes for the most innovative ways to “repair the planet”.
Mr Khan will use the four-day trip to “bang the drum” for the capital by seeking to attract US firms to expand in London and encouraging tourists to visit.
But he can expect criticism for travelling 7,000 miles while urging others to become greener. He said “only in exceptional circumstances” were global gatherings done in person.
Last year it was estimated that he and his aides had clocked up more than 360,000 air miles since he became mayor in 2016.
Susan Hall, the Tory mayoral candidate, accused Mr Khan of “swanning off to America to lecture everyone” while Londoners were being hit by the “disastrous” Ulez expansion, which she pledged to axe if elected next May.
The cost of the trip will be paid by the C40 group of world cities committed to action on climate change, which Mr Khan chairs. He was invited to the climate summit by UN Secretary General António Guterres.
The UN General Assembly is an annual event attended by world leaders. It is not known whether Mr Khan will be able to address the General Assembly but will attend the climate summit, which is part of the wider gathering.
While Mr Khan will not be able to share any data about the impact of last month’s Ulez expansion to the Greater London boundary, he expects to be asked about the wider benefits of what is the world’s largest clean air zone.
He will say there is “no time to delay” action to tackle climate change.
The visit, which is taking place during New York climate action week, will involve Mr Khan meeting New York mayor Eric Adams, former mayor Mike Bloomberg and attending an event at the Clinton Global Initiative.
Mr Khan is also due to speak at Columbia university and attend a business reception hosted by London & Partners, the tourism and investment agency.
He last visited the US in May last year, when a five-day trip took him to New York, Los Angeles and San Francisco.
Latest figures show the number of US visitors to London is almost back at pre-pandemic levels. The number of scheduled flights from North America to the capital this year is up two per cent compared with 2019.
Mr Khan said: “I am looking forward to visiting New York where I will be banging the drum for London, showcasing our capital as the perfect destination for businesses to invest in and tourists to visit as I continue working to build a more prosperous London for everyone.
“I’ll be meeting many leading businesses and investors during my stay and reminding them that there is nowhere better than London on the planet to set up, or grow your business.
“I am also honoured to have been invited to participate in this key summit taking place during the United Nations General Assembly about climate change, the biggest global threat we face today.
“I am determined for London to continue being a world leader in tackling the twin dangers of air pollution and the climate emergency. My visit to the UN is an opportunity to learn from other cities and nations and ensure London remains at the forefront of global action.”
Tony Devenish, City Hall Conservatives environment spokesperson, said: "He has declared himself to be the ‘greenest mayor’ yet his office has reportedly accumulated over 360,000 air miles since he became mayor.
“His latest trip, to attend a climate summit, will add even more air miles to that total, contradicting his so-called green credentials.”
Mark Watts, executive director of C40, said: “The UN Climate Ambition Summit follows the hottest summer ever recorded on earth. Clear, rapid leadership on climate is needed now more than ever to urgently phase out fossil fuels and ensure a liveable planet for all.”
