Answer : 1. "INS Shalki"
Explanation :

INS Shalki is the first indigenously built submarine in India. It is part of the Shishumar class of submarines and was commissioned into the Indian Navy on December 7, 1991. INS Shalki, along with its sister submarine INS Shankul, marked a significant achievement in India's naval capabilities as it was built at the Mazagon Dock Limited in Mumbai, showcasing the country's growing capacity to design and construct submarines domestically.