BEIJING: China has completed constructing one of its longest tunnels which will help it build a rail link with Pakistan. It has also announced plans for building the world’s longest undersea tunnel measuring 123 km to link two major cities.

The completed tunnel runs 22.24 km in the mountainous Xinjiang Uygur Autonomous Region and will reduce the distance between Turpan with Korla in southern Xinjiang by 122 km. At present the distance between these two points on the Nanjiang Railway is 334 km.

Sources said the tunnel is part of China’s efforts to prepare the relatively backward Xinjiang to take advantage of the planned China-Pakistan economic corridor. Chinese leaders are also betting that enhanced economic development will help soften the ongoing bloody movement among a section of Uygur Muslims in Xinjiang.

Chinese engineers have now announced a $30 billion undersea tunnel which will be more than double the size of the existing record holder, the Channel Tunnel. It will knock off nearly 1200 km of travel from the northern Chinese city of Dalian to Yantai on the east coast.

“Work could begin as early as 2015 or 2016,” the China Daily quoted Wang Mengshu, an expert at the Chinese academy of Engineering, as saying. The tunnel will also form a vital link in a high-speed rail line from the frozen parts of northern China to the tropical island of Hainan in the south.

Construction of the ambitious tunnel will require epic engineering skills demonstrated by China during the building of Tibet railway over frozen mountains, sources said. The tunnel passes through two earth quake fault lines. This includes Tangshan city, which was destroyed in 1976 after a 7.5 magnitude earthquake.