The key nod - cabinet clearance - to Patna Metro rail project came on Tuesday evening.

The ambitious project, a brainchild of chief minister Nitish Kumar, aims at easing traffic congestion in the capital and is likely to be completed by 2021.

The cabinet also decided that a special purpose vehicle (SPV) would execute the project with a cost component of Rs 16,960 crore.

The SPV to execute the metro project would be named as Patna Metro Rail Corporation and both the Union and state governments would contribute 20 per cent each of the project cost whereas the state government have approached international financial agencies like Japan International Cooperation Agency (JICA) and Asian Development Bank (ADB) for remaining 60 per cent. Sources claimed that the JICA is most likely to be approached to seek financial assistance for the project.

State urban development and housing department principal secretary Amrit Lal Meena said the JICA and ADB had been requested to extend financial assistance for the mega project.

At present, the ADB is set to fund the Kachchi Dargah-Bidupur six-lane bridge on the Ganga while the JICA has already assisted financially for the four-lane project of Patna-Gaya-Dobhi. The latter has also extended technical assistance to Gandhi Setu.

The state government would soon send the Patna Metro detailed project report (DPR) to the Centre for seeking financial and technical assistance. Senior officials in the urban development and housing department claimed that if things fall in order then actual construction works on the metro rail project might start within a year-and-a-half.

Cabinet coordination department principal secretary Brajesh Mehrotra told reporters that the Metro rail project was among the 51 proposals passed by the cabinet at its meeting chaired by Nitish on Tuesday.

The Metro network would cover a distance of about 31km with 27 stations on the two routes initially.

While the east west route would cover the area from Saguna Mor to Patna Junction, the north-south route would cover places from Patna Junction to Bairiya via Gandhi Maidan and Patna Medical College and Hospital.

Of 31km network, 16km would be underground while the rest would be elevated. Sources claimed that the cost of constructing underground Metro rail corridor is around Rs 400 crore per km while that of elevated corridor is around Rs 200- 250 crore per km.

Reacting to the cabinet nod, urban development and housing department minister Maheshwar Hazari said: "The Metro rail project was a priority for the state government, which is keen to begin construction work as soon as possible."

The work on Metro rail project has apparently been progressing at a snail's pace till now. Indian Railways in March 2009 had appointed RITES (earlier known as Rail India Technical and Economic Service) as technical consultant for examining the feasibility of Metro as well as monorail in Patna. RITES, in its feasibility report, had ruled out the possibility of running monorail and had given a green signal to Metro.

The Metro rail detailed project report was given an in-principle approval by Nitish during a review meeting of the department held on December 22, 2015, and he asked officials to get the project approved by state cabinet within three months.