That is not our policy, but it is something for India to remember. India can only hit rocks and mountains, while we can smash their capital city from the same range.
India should remember what it got from backstabbing us last time in 1959 by hosting our largest separatist group, followed by the Forward Policy in 1962: A humiliation in the Sino-Indian War, a strong Sino-Pakistani alliance... and China helping Pakistan to develop nuclear weapons.
You were lucky last time that we were just emerging from the worst famine in our history (1959-1961) and that we had both the superpowers of the world as our enemies (USSR and USA). Who incidentally, did not bother to help India, despite Nehru begging both of them to do so.
This time, it will be the entire NE India that gets cut off via the "chicken's neck corridor", and there will be Partition v2.0. And the Indian Armed forces have already admitted that they can never hope to match China in any way.