The index is now down 197 points at 11,175.
Earlier in the day the Sensex opened at 11,371 and advanced to 11,376. Thereafter, the index slipped into the red and touched a low of 11,161.
Sterlite, DLF and Tata Steel have slumped 4% each to Rs 397, Rs 234 and Rs 244, respectively.
Reliance Infrastructure has plunged 3.5% to Rs 685. Tata Motors, Reliance Communications, HDFC and Bharti Airtel have shed 3% each.
Tata Power, ICICI Bank and ITC have declined 2.5% each to Rs 840, Rs 455 and Rs 188, respectively.
Hindustan Unilever, ACC, Wipro, ONGC, Hindalco, BHEL, Larsen & Toubro, NTPC, Grasim and HDFC have dropped 1-2% each.
However, Mahindra and Mahindra and Sun Pharma have advanced more than 1% each to Rs 481 and Rs 1,242, respectively.
Jaiprakash Associates and Infosys have also moved up.
The market breadth is fairly negative. Out of 2,237 stocks traded, 1,489 have declined and 671 have advanced.