The Sensex opened marginally (24 points) lower at 17,204 amid weak cues from the global markets. The index soon dropped to a low of 17,111, and is now down 47 points at 17,181.
The NSE Nifty is down 13 points at 5,135.
Tata Steel and Sterlite have slipped 1.5% each to Rs 560 and Rs 850, respectively.
Hindalco and ICICI Bank are the other significant losers.
Sun Pharma and ONGC are the notable gainers.