After rising to 18,567.70 at the outset, the 30-share index fell sharply to trade at 17,853.05, down 2.17 per cent, at 1500 hrs.
The broad-based National Stock Exchange index Nifty fell by 107.55 points, or 1.99 per cent, to 5,293.90 as the rupee slumped to a new record low of 64.43 per dollar.
Marketmen said the selling pressure was more confined to companies such as software exporters and drug makers with their exposure to overseas markets.
Infosys, the second-largest software services provider, dropped 2.12 per cent to Rs 2,941.45.
Sun Pharmaceutical, the most valuable drugmaker, fell by 4.23 per cent to Rs 486 while Cipla decline by 1.82 per cent to Rs 393.85.
State Bank of India plunged by 1.06 per cent to Rs 1,537.10, after climbing to Rs 1,650 in early trade.