India’s only military defeat was at the hands of the Chicoms in 1962-they still hold thousands of square miles of Indian territory in the North East & Kashmir(gifted by their allies,the Pakis).India’s Prime Minister back then,Nehru gave a go ahead into the feasibility of nuclear weapons a little after the war.Everytime,India mobilised it’s military for war against Pakistan,the Chicoms would mobilise their border divisions or threatened to do so,tying down Indian forces on their borders.
India doesn’t need any ballistic missile for simple deterrence against the Pakis.