The $US 84bn project is the world’s first maglev mainline railway and would achieve speeds of 500km/h, cutting travel times between Tokyo and Nagoya to just 40min, compared to 1h 38min by Nozomi Shinkansen trains currently.

Mr Heita Kawakatsu, governor of Shizuoka prefecture, reiterated his refusal to permit construction of an 8.9km stretch of tunnel in his jurisdiction due to fears that it would divert water from naturally flowing into the Oi river and potentially disrupt water supply to the local area.

The Southern Alps tunnel is planned to extend 25km across the borders of the Yamanashi, Shizuoka and Nagano prefectures, stretching under the Akaishi mountains, an area of the Japanese Southern Alps. The tunnel is expected to be the deepest in Japan upon completion, with 1.4km of mountain above it.

However, construction work in Shizuoka has stalled due to concerns about the ecological impact of the tunnel. The tunnel is planned to pass near the source of the Oi river, a major waterway which flows south through the prefecture. The tunnel will slope downward at both ends, and there are fears that this could significantly redirect water flow into the river.

Although plans to construct a channel to redirect water back into the river were presented by JR Central to the prefectural government in 2017, it is estimated that the tunnel will decrease the flow of the river by up to 2 tonnes per second during construction according to a report by the company in 2013.

Mr Kawakatsu cited concerns by local farmers and environmentalists that the tunnel could affect the quantity and quality of water in the Oi river and potentially jeopardise the area’s agricultural industries.

“Of course, we are not against the maglev project itself,” said Mr Kawakatsu in a live-streamed meeting with JR Central chief executive Shin Kaneko. “But the towns and people of Shizuoka and everybody in Japan who relies on well water are thinking the same thing, which is what happens if the water is diverted.”

Construction began in 2014, and the first section of the line, between Tokyo and Nagoya, was originally scheduled to open in 2027. However, the tunnel dispute is expected to extend construction times and potentially increase costs significantly.

In addition, resistance in Shizuoka has been compounded by the fact that the Chuo Shinkansen will not have a station in the prefecture and is intended to bypass the existing Tokaido Shinkansen which runs through the prefecture’s southern coastal region.

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