The Indian equity benchmarks resumed their downward journey after a pause of two sessions on Wednesday as investors turned to profit booking at higher levels amid heightened volatility, analysts said. The benchmarks staged a gap up opening but gave up intraday gains and turned choppy during the second half of the session. The Sensex fell as much as 520 points from the day's highest level and Nifty 50 index touched an intraday low of 16,211 after hitting high of 16,400.