The Indian equity benchmarks fell for third session in a row on Tuesday dragged by losses in heavyweights like Reliance Industries, HDFC, HDFC Bank, Hindustan Unilever, ICICI Bank and Maruti Suzuki. The benchmarks witnessed heightened during the session owing to lack of supportive cues from global markets after two days of carnage on Dalal Street, analysts said. The Sensex fell as much as 636 points from the day's highest level and Nifty 5 index touched an intraday low of 15,659.45.