A fourth London council has voted to oppose a new £2bn road tunnel under the Thames in east London, putting the capital’s mayor at loggerheads with local authorities over his biggest infrastructure project. Sadiq Khan accused councils of “want[ing] to put off tough decisions”, after Greenwich councillors voted overwhelmingly to call for all work on the Silvertown tunnel to be paused immediately. The vote means that both of the boroughs that would be primarily served by the tunnel now oppose it. Silvertown would link Greenwich peninsula with Royal Dock in Newham, where councillors two weeks ago voted for the tunnel to be cancelled. Lewisham and Hackney councils voted to oppose the tunnel in 2015. Khan insists the tunnel, in combination with new bus routes, road charging and emissions control schemes, will reduce congestion. But opponents say the new road would bring increased traffic, especially from lorries, and that any successor to Khan could eliminate the tolls he says will deter drivers. Khan spoke to journalists on Thursday about a City Hall analysis showing black and Asian Londoners were more likely to suffer the impacts of the climate emergency. He denied Silvertown, a major road project in the middle of some of the UK’s most diverse and deprived communities, stood in contradiction to his stance on environmental justice. He suggested opponents of the scheme did not understand the reality of living in the area, which lacks the “abundance of bridges and crossings” enjoyed by residents in the city’s wealthier western boroughs. “Those doctors campaigning against this may not live in that part of London, some of those people you are talking about who object may not be stuck in the traffic,” Khan said. “But the consequences of those who are stuck in traffic is poor quality air suffered by the children playing in the playgrounds around their schools, and the residents who can’t use their gardens safely because of the particulate matter and nitrogen dioxide.” Nevertheless, the Greenwich vote, after years of equivocation, leaves Khan politically isolated over Silvertown, a scheme he inherited from Boris Johnson’s tenure as London mayor. It is thought the council’s Labour leadership finally allowed a vote on the scheme after internal party wrangling, and fears it could be an issue in forthcoming local elections. “I can understand with elections approaching why people want to put off tough decisions,” Khan said. He said his administration had improved on Johnson’s plans, adding: “It would have been really easy, by the way, for me to cancel altogether those plans in 2016. But it doesn’t solve the problem in that part of London, it is putting your head in the sand. I’m not willing to do that.” Simon Pirani, of the Stop the Silvertown Tunnel group, rejected Khan’s claim that campaigners against the tunnel were not locals to Newham and Greenwich. The retired energy researcher, who lives in Greenwich, said that, on the contrary, he and fellow campaigners had struggled to raise awareness outside the immediate area. “We are thrilled that Greenwich council has changed its mind after its leadership has spent months trying to prevent a discussion about this,” Pirani said. “This gives us hope that the mayor of London too can come to his senses, even at this late stage, and pause the project for a proper review.”