The world’s biggest box culvert machine began digging beneath the city’s Middle Ring Road from Tuesday on a tunnel that will connect Xuhui and Minhang districts. The concrete box culverts, over 19 meters long and 6 meters tall, will be pumped into the soil beneath the ring road on Tianlin Road for the kilometer long tunnel. Once completed, the tunnel is expected to ease traffic congestion in the Caohejing area. Completion is anticipated at the end of 2018 and the tunnel will open to the public in March 2019 after decoration and equipment installation, according to STEC Shanghai Urban Construction Municipal Engineering Group.