Sensex tanks 709 pts from day's high, ends 311 pts down; Nifty holds 17,500
F&O Expiry: 25 of the 30 Sensex constituents and 34 of the 50 Nifty constituents ended in the negative territory including Adani Ports, Bajaj Finance, IndusInd Bank, Infosys, TCS, Axis Bank, and HDFC
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