Equity benchmark Sensex plunged 886 points on Thursday, tracking heavy losses in index heavyweights Reliance Industries, HDFC twins, Infosys and ICICI Bank amid a selloff in global markets. After crashing over 955 points during the day, the 30-share index settled 885.72 points or 2.77 per cent lower at 31,122.89. Similarly, the broader NSE Nifty tanked 240.80 points, or 2.57 per cent, to 9,142.75.