The official name for the tunnel is the Thames Tideway Tunnel, and its purpose was to reduce the amount of raw sewage entering the river.
The 16-mile (25-kilometer) conduit is expected to redirect thirty-four of the most polluted sewage outflows (CSOs) that have been entering the Thames.
Critics claim that the tunnel’s lifespan may be restricted due to climate change.
“This is the moment we’ve all been waiting for,” Thames Tideway CEO Andy Mitchell told BBC News from a boat above the Thames tunnel.
“We’re going to capture the vast majority of the sewage that comes into the river, and it will mean a cleaner river.”
The last stage involves lifting a massive 1,200-ton concrete cover atop an east London shaft. It is anticipated to happen during the following few days.