NEW DELHI: India is in final talks with Russia to lease a new nuclear attack submarine, giving a much needed boost to its depleting underwater fleet. Signaling a difference in approach by the Modi-led government, India is now looking to lease a newly built, customised submarine, unlike in the past when older vessels were refurbished and handed over.Several sources related to the project that ET spoke with confirmed that talks on leasing a new submarine under the ‘Chakra 3’ project are in advanced stages and that the issue will be discussed during Prime Minister Modi’s visit to Russia this week.India has the ‘Chakra 2’ Akula class nuclear submarine in service that is considered to be one of the deadliest non-US attack boats in the world. This submarine – a refurbished Soviet era boat – has been taken on a 10-year lease from Russia in 2012. ‘Chakra 1’, India’s first nuclear submarine, was taken on a similar lease in the late 1980s.While talks on leasing a third Chakra have been on for over two years, a change of stand has taken place after the Modi government took over, with the Indian side insisting on a modern, world-class submarine on lease. The only nuclear attack submarine of this kind being produced in Russia currently is the Yasen class, the quietest, least detectable submarine it has ever built.It is still not clear, however, whether the final contract would specify a Yasen submarine or a modified boat of the same class to suit Indian requirements. "The final shape is yet to be decided, but it is now almost certain that a ‘greenfield’ submarine will be built," a source associated with the programme told ET.What is clear is that India is embarking on a project to produce indigenous class of nuclear attack boats (SSNs) under new submarine programme. The plan, to build at least six SSNs in India, was given financial sanction in February and designers are already at work on the project that could cost upwards of Rs 90,000 crore.These new submarines, to be fitted with the indigenous verticallylaunched Brahmos missile, are to be built at the Vizag-based ship building centre, with L&T expected to get a significant chunk of the work.Work on making operational India’s first nuclear missile boat – different from a nuclear attack submarine is also underway with the first missile test from the submarine expected to take place this year.