The Sensex was trading down by 500 points or 1.2% at 40183.27 by afternoon on Monday. Nifty was down 170 points at 11,756.
The market witnessed profit booking with the Sensex opening at 40,649.76 and touching a low of 40,107.86.
Nifty Auto Index slipped more than 3 percent dragged by the Hero MotoCorp and Bajaj Auto which fell more than 5%.
Tata Motors and Ashok Leyland fell 3.5% each to trade at Rs 131 and Rs 79 respectively. Amara Raja Bhatt and MRF were the only stock in the green.
The Index has given a return of 32% in last 6 months.
