NS Arihant, India’s first indigenous nuclear submarine, has completed its first deterrence patrol, Prime Minister Narendra Modi said on Monday, describing the submarine as a fitting response to those who indulge in nuclear blackmail.br br In a series of tweets that included a rare photograph of the submarine, PM Modi said the first deterrence patrol marks the successful establishment of India’s nuclear triad that gives India the capability to launch nukes from land, air and sea.