that the use of a low-yield battlefield weapon would not be seen as provocation enough by India or the international community to merit nuclear retaliation.
NEW DELHI: India will retaliate massively even if Pakistan uses tactical nuclear weapons against it. With Pakistan developing "tactical" nuclear warheads, that is, miniaturizing its weapons to be carried on short-range missiles, India will protect its security interests by retaliating to a "smaller" tactical attack in exactly the same manner as it would respond to a "big" strategic attack.
http://articles.timesofindia.indiatimes.com/2013-04-30/india/38928972_1_pakistan-shyam-saran-india