Young people concerned about the climate crisis and air pollution are urging the Mayor of London, Sadiq Khan, to abandon his plans for a new four-lane road tunnel under the Thames, or risk losing their support.

Climate justice activists, anti-pollution activists and key youth groups within the Labor Party say Khan, who runs for reelection on Thursday, is ignoring climatologists, economists and health experts by suing the £ 2 billion Silvertown tunnel project in east London.

They warn that unless he rolls back the plans he and Labor could lose the support of a generation of young voters.

Anjali Raman-Middleton, co-founder of the Muffled Anti-pollution campaign put together by a group that describes themselves as’ black and brown teenagers from south London ‘said:’ This is becoming a real problem. The tunnel risks losing the support of the younger generations because it is we who will have to live with the consequences of this decision in the years to come… It gives us the impression that we have no one to vote for to really get this stuff and who is ready to act.

Gaya Sriskanthan, co-chair of Momentum, the grassroots Labor campaign group, said the UK would struggle to meet its climate targets if “fossil fuel infrastructure” like the Silvertown Tunnel moved forward.

“Time and time again we have seen politicians lip-smacking about the climate emergency, agreeing to goals on paper, but failing to act when it really matters,” she said. “Failures like this will cause young voters in the Labor Party to lose hope when it should be the party leading climate action.”

The tunnel would be built near the existing Blackwall tunnel in east London and carry four lanes of traffic – two in both directions. Last year, the Guardian revealed that the project could cost nearly £ 2 billion over the next three decades if it comes to fruition.

The Khan administration has repeatedly defended the project, saying it is essential to improve river crossings in east London – especially the Blackwall Tunnel – which are “run down and worn out” and claim that the tunnel would reduce pollution.

The plans met opposition from a growing list of MPs, councilors, environmentalists, health experts and residents. They say it will increase pollution, increase car use and increase emissions in one of the most disadvantaged and polluted parts of the capital for years to come – all as the climate crisis accelerates .

The shadow climate change minister, whose constituency of Greenwich and Woolwich would contain one end of the tunnel, called on Khan to reverse the plan. Lyn Brown, Labor MP for West Ham, where the other end of the tunnel would be, also called for the project to abandon.

At least eight constituency Labor groups have also passed motions opposing the plans in recent months.

Izzy Hickmet, of Labor for a Green New Deal, who grew up near the proposed tunnel site, said it would “undo a lot of the good work Sadiq has done for the environment since he became mayor”.

“There is a clear choice here: between a continued reliance on cars and building the cheap, clean, public public transport we need to tackle the climate emergency.”

Hickmet added: “Unfortunately, this is part of a larger picture of Labor which is watering down its environmental policies. This has led a significant number of young voters to turn away from the party – which will only get worse if Sadiq Khan continues to support the Silvertown Tunnel, ignoring expert opinion and widespread opposition within our party.

Last month, some of the UK’s leading climatologists, economists and health experts signed an open letter Calling for the program to be abandoned, saying it was incompatible with the UK’s legally binding climate targets and London’s own declaration of climate emergency.

‘It would be unwise to go ahead with an infrastructure project that can only contribute to the UK’s excessive greenhouse gas emissions – while also shifting London’s transport system more towards roads and by exacerbating local air pollution problems, ”they wrote.

A Labor spokesperson defended the project, saying the existing Blackwall tunnel “had caused huge problems in central London for many years”.

“The Silvertown Tunnel is a project that Sadiq inherited and has been upgraded and it is the only viable alternative to reduce the poor air quality and massive congestion caused in the area by the Blackwall Tunnel.

They added that the £ 2bn cost of the new tunnel would be covered by charging a toll for the use of both the existing Blackwall and the new Silvertown tunnels.

However, campaigners say the mayor could toll the Blackwall Tunnel, reducing congestion and air pollution, with the money raised spent on public transport and improving walking and cycling infrastructure rather than ‘a new four-lane tunnel.

Khan leads the polls ahead of Thursday’s vote with Tory rival Shaun Bailey in second place.

The Labor spokesperson described it as a ‘two-horse race’ adding: ‘If you want a green mayor at town hall, you have to cast your vote for Sadiq Khan. [or risk] wake up with a conservative mayor.

However, Raman-Middleton, of Choked-Up, warned Khan and the Labor Party not to take young people for granted.

“I think the Labor Party is getting pretty complacent. He thinks he can count on the youth vote, but he won’t be able to if he continues to push policies like this one, ”she said.