Kolkata, the first Indian city to get a metro railway network, will set another precedent by having an underwater rail connection. The Union cabinet on Thursday approved the much-awaited extension of the Kolkata metro with its neighbouring city Howrah, which will include a tunnel under the Hooghly river.

The project, estimated to cost Rs 4,676 crore, will connect one of the busiest railway stations of eastern India, Howrah, and the information technology suburb of Salt Lake.

The link will cover 13.77 km with 8 km running underground. The project will be executed through a 50:50 joint venture company, to be formed between the West Bengal government and the Centre. JBIC of Japan will partially fund the metro link, sources added.

The Cabinet today approved the constitution of a Special Purpose Vehicle for the project.

"The SPV will be constituted for the successful execution of the project as well as its operation and maintenance," Information and Broadcasting Minister Priya Ranjan Dasmunsi said.

The project is expected to be completed in six-and-a-half years in two stages. The first stage, the 5.77 km, elevated section, is expected to be commissioned in five-and-a-half years.

The project report, which was prepared by Delhi metro chief E Sreedharan, stipulates a two-tier fare structure of Rs 8 and Rs 16.

Although the original proposal was to extend the link 3.5 km inside Howrah district, the cabinet approved the rail line till Howrah station.

Dasmunsi, who also heads the All India Football Federation, was visibly happy announcing the project, saying it would enable soccer fans across the river easy access to the Salt Lake football stadium.

According to sources, Planning Commission Deputy Chairperson Montek Singh Ahluwalia insisted that the project be referred to a Group of Ministers. He also said that the Centre should not bear any financial responsibility and the project should be left to the state for execution.

However, Dasmunsi argued that in Chennai and Bangalore the metro links have central participation and Kolkata should get similar treatment.