The Sensex today tanked over 160 points in opening trade on major sell-off by funds and retail investors amid slumping global markets. The 30-share index, which had lost over 240 points in the previous session, plunged by 160 points, or 0.91 per cent, to 17,374 points. All the sectoral indices, led by metal and realty, were trading in the negative territory with losses up to 2.74 per cent. The wide-based National Stock Exchange index Nifty dipped by 46.15 points, or 0.87 per cent, to 5,210.