After regaining 19,000-level at the outset, the Sensex plunged by 390.10 points, or 2.2 per cent to 18,496.03 with all the sectoral indices losing up to 2.67 per cent.
Similarly, the broad-based National Stock Exchange index Nifty dropped by 129.20 points, or 2.3 per cent to 5,421.55 driven by stocks of HDFC, ITC and RIL.
Brokers said investors confidence remained jittery as the rupee again dipped below 67 per dollar, raising fears of widening fiscal deficit.
The most heaviest on the benchmark with their nearly 20 per cent weightage - Reliance Industries plunged 3.93 per cent to Rs 849 and ITC by 2.79 per cent to Rs 310.50. HDFC, also a index kitty stock, dropped by 4.21 per cent to Rs 704.75.