With the INS Arihant now becoming fully operational, India has joined the 'Nuclear triad' club of superpowers who can launch nuclear weapons from sea, land and air-based systems, reports News X.

INS Arihant, a 6,000-tonne submarine, is country's first indigenous nuclear submarine and can launch nuclear weapons from underwater. The vessel was declared as ready for operation in February 2016. It was built under the Advanced Technology Vessel Project at the Ship Building Centre. In August 2016, INS Arihant had been commissioned by PM Modi into the Indian Navy.

An advantage of such a submarine is that they are harder to track and destroy than land and air nuclear launch platforms.

India has now joined group of five other elite countries - USA, UK, France, Russia, China - to have developed nuclear-armed submarines.

INS Arihant gives India the power to hold the threat of a 'second strike' in a nuclear counter attack, even if the country is completely destroyed. This finds relevance in India's 'No First Strike' policy in contrast to Pakistan's "First strike" policy. The 'First Strike' policy allows Pakistan to use nuclear weapons against India even if India does not.