After three days of gains, the 30-share BSE Sensex tumbed 561.46 points, or 0.72 per cent, to settle at 77,054.94. During the day, it tumbled 614.92 points, or 0.79 per cent, to 77,001.48. The 50-share NSE Nifty dropped 158.95 points, or 0.66 per cent, to end at 24,052.05.
