The Indian equity benchmarks edged lower on Tuesday after investors resorted to profit booking in HDFC and HDFC Bank a day after they staged a massive up move on merger plans. Recent outperformers like Reliance Industries, Kotak Mahindra Bank and Bharti Airtel were also facing selling pressure on account of profit taking. The Sensex fell as much as 246 points and Nifty 50 index slipped below its important psychological level of 18,000.