Kolkata: A day after Ratan Tata said he could not see much of industrial activity in West Bengal, state Finance and Industries Minister Amit Mitra hit back, saying the Tata Sons chairman emeritus has "gone off his head".

"He should carry on with his hobby of flying. I am surprised that his company officials did not brief him properly. He does not know about the expansion of his own group companies in West Bengal... he has gone off his head," Mitra told mediapersons here.