Kolkata, Aug 21 - The Dredging Corporation of India (DCI) will buy three dredgers of 5,000 cubic metre capacity each at a total cost of Rs.1,722 crore.

'The Public Investment Board (PIB) has approved the purchase Wednesday. It will now be put before the cabinet committee on infrastructure. But after the PIB nod, the rest of the process is a mere formality,' joint secretary (ports and administration) of the shipping ministry Rakesh Srivastava told reporters.

The dredgers, to be bought from world's leading dredger makers I.H.C. of Netherlands, will be in operation by 2013.

Asked whether the government was planning to allow individual ports to purchase dredgers, Srivastava replied in the negative.

'We don't encourage that because dredgers are needed by an individual port for 15 days in a year on an average. Instead, we encourage hiring of dredgers,' the official said.

Srivastava was in the city to attend a meeting chaired by Minister of State for Shipping Mukul Roy on maintaining the requisite depth and draft of the Haldia dock system under the Kolkata Port Trust (KoPT).

The navigability of the dock system has gone down due to increased siltation that has choked its channels.