The National Coalition was the only political party in favour of expanding a tunnel below Helsinki's city centre to ease traffic congestion when councillors met to discuss the issue on Wednesday.
The Helsinki city council decided that it would not support plans to build an underground tunnel that would run seven kilometers from Helsinki's Sörnäinen district to the West Harbour.
The Social Democrats, with 12 seats on the 85-member council, tipped the balance in favour of the nays.
The SDP said the 1.4-billion-euro price tag was too expensive and that resources should instead be directed towards making Helsinki more walkable and improving public transit.
“Developing public transport means improving access and lowering fares,” SDP councilor Eveliina Heinäluoma said.
The Greens and Left Alliance have also said they reject the building of the tunnel.
Proponents for the tunnel project have argued that it would offer an underground route for harbour traffic. To that end, the SDP proposed concentrating harbor traffic in Helsinki’s eastern Vuosaari district.
“This is a loss for Helsinki residents,” said Risto Rautava, a Helsinki city council member for the National Coalition Party, who has been a proponent of the tunnel, calling subterranean traffic the way of the future.
Meanwhile, commenting on the council's decision from New York City, Helsinki Mayor Jan Vapaavuori told Helsingin Sanomat, "In 20-30 years' time when there are fewer work places and services in the city, the traffic's a mess and harbours are struggling, we'll know whom to blame."