Stock market today: BSE Sensex back in red, plunges 600 points; Nifty50 near 21,300

Stock market today: India's benchmark equity indices, BSE Sensex and Nifty50, opened lower on Thursday amid mixed global cues, pulled down by information technology stocks due to weak Q3 results from Tech Mahindra. BSE Sensex plunged as much as 600 points in intraday day trade till the time of filing.