The Project 75I-class submarine is follow-on of the Project 75 Kalvari-class submarinefor the Indian navy. Under this project, the Indian Navy intends to acquire 6 diesel-electric submarines, which will also feature advanced Air Independent Propulsion (AIP) systems to enable them to stay submerged for longer duration and substantially increase their operational range.
The P-75I submarines will be more modern and advanced with all of them equipped with Air Independent Propulsion modules to enhance the reach and stealth characteristics. AIP modules were not part of the Scorpene deal, and the Navy is trying to have them fitted on the last two Scorpenes. That is contingent on the timely delivery of the AIP being indigenously developed by the Defence Research and Development Organisation.