Here is your 10-point cheatsheet on the Kalvari:
The diesel-electric submarine weighs 1550 tonnes, is 6.2 meters in diameter and 67 metres long.
The six Scorpene submarines are being built by the state-run Mazgaon Docks Limited or MDL in Mumbai in collaboration with DCNS of France in a $3.6 billion (Rs 20,000 crore approximately) contract signed in October 2005.
The Kalvari is likely to be commissioned in September 2016 after a year of sea trials.
30% of the equipment on the Kalvari is made in India. The pressure hull of the submarine has been manufactured by MDL.
The sub will carry anti-ship torpedoes and missiles.
The other five submarines will be delivered one every nine months.
The project has over-shot both time and budget. MDL officials today said they expect to complete the order by 2020.
India's Navy currently has 13 ageing diesel-electric submarines, only half of which are operational at any given time due to refits.
To replace a nearly 30-year-old fleet hit by a run of accidents, Prime Minister Narendra Modi's government has ordered an accelerated tendering process to build six conventional diesel-electric submarines at an estimated cost of Rs. 50,000 crore ($8.1 billion), in addition to the Scorpenes.
The country's first indigenously built nuclear submarine, INS Arihant joins the fleet late next year.