The boring beneath the Thames to form the Silvertown Tunnel has been completed, Transport for London (TfL) has said.
Due to open in 2025, the 1.4km river crossing will link Silvertown, in Newham, with the Greenwich Peninsula.
The project has received criticism, with opponents arguing it will increase emissions in the area, reports the BBC.
TfL has said the scheme will address issues with the Blackwall Tunnel and reduce pollution.
The Blackwall Tunnel is the only major crossing of the Thames in east London and often suffers from closures and heavy traffic.
The Silvertown Tunnel will be the city’s first road tunnel in over three decades, said the BBC report.
Helen Wright, head of the Silvertown Tunnel Programme at TfL, has said the project will “support growth in the local area, provide new public transport connections across the river via zero-emission bus routes and address the chronic issues Londoners face at the Blackwall Tunnel”.
However, Siân Berry, a Green member of the London Assembly, believes the scheme will increase car dependency and cause pollution.
She previously authored a report proposing alternative uses for the tunnel, such as for a tram system or as an extension to the Docklands Light Railway (DLR).
This week, she called on Mayor Sadiq Khan to “make this real blot on his record turn into something more positive”.
In September, Mr Khan defended the Silvertown Tunnel on BBC Radio London, saying the east of London had been “neglected for centuries”.