"We are planning to seek a private agency for the project. Details are being worked out and will be sent to the government for approval," P.R. Baviskar, chief executive officer of the Calcutta Metropolitan Development Authority (CMDA), said on Sunday.

According to Baviskar, the work will be carried out on a public-private participation basis. "It will be executed on a build-operate-transfer (BOT) basis," he added.

There are several models of BOT and the authorities are working out the best possible model, he said. There had been a proposal for imposing a toll tax on the Bypass to raise the cost of construction but it was rejected.

"Since it is a city road, the toll tax concept was ruled out. There are other possible models on which we are working," Baviskar said.

It will take another four to six months to begin the work of widening the road. "There are several technical procedures, but the ball has been set rolling," Baviskar said. According to him, the project cost was being worked out.

"We are waiting for April, when we will know how much money will be allotted for the work by the Centre under the megacity project," the CMDA CEO said.