Source : Indian Defence Updates (IDU)

Amid the delay in the Project-75I to build 6 advanced submarines, the Indian Navy will soon approach the Defence Acquisition Council (DAC) for the grant of Acceptance of Necessity (AoN) for the construction of 3 more Kalvari class diesel electric submarines at Mazagaon Dock Shipbuilders in partnership with France’s Naval group.
Indian Navy to approach DAC for the approval of 3 more Kalvari class submarines
All the three submarines will be fitted with the DRDO developed Air Independent Propulsion (AIP) system while the existing 6 Kalvari class submarines will get the Air Independent Propulsion system during their midlife refit.