Context: Recently, Indian Navy’s third stealth Scorpene class (of Project-75) Submarine INS Karanj has been commissioned at the Naval Dockyard Mumbai.
The History of Karanj

• The earlier version of the submarine, which belonged to the Foxtrot class, was first commissioned in 1969 at Riga in the erstwhile USSR.
• A proposal to form a submarine arm, also referred to as the silent arm, of the Indian Navy was first envisaged in 1959, but it was only in 1964 that the Soviet government agreed for transfer by purchase for four Foxtrot-class submarines, of which INS Karanj was a part.

About INS Karanj

• It is India’s third Scorpene-class diesel-electric submarine.
• The two submarines of this class, INS Kalvari and INS Khanderi, have already been commissioned into the Navy.
• The fourth of the class, INS Vela, has been undergoing trials at sea.
• The Scorpene-class diesel-electric submarines are one of the quietest conventional submarines currently in service around the world.
• The submarines have been designed by France’s Naval Group and built in India by Mazagon Dock Limited under Project 75.
• The Scorpene-class submarines will be fitted with indigenous air-independent propulsion systems after successful trials of the system.
• The Kalvari-class submarines can be deployed in different roles which include guarding strategic points in the sea, laying mines, gathering intelligence, dropping marine commandos and engaging with enemy ships when required.

6 Scorpene-class submarines, also known as Kalvari Class, are being built in India by the Mazagon Dock Shipbuilders Limited (MDL) Mumbai, under collaboration with Naval Group, France. Their names are

1. INS Kalvari: Commissioned in 2017
2. INS Khanderi: Commissioned in 2019
3. INS Karanj: Commissioned in 2021
4. INS Vela: Under Sea Trials
5. INS Vagir: Under Sea Trials
6. INS Vagsheer: Under Construction?