The 30-share BSE barometer started on a negative note and fell further to touch the day's low of 22,286.26. It closed down by 184.52 points, or 0.82 per cent at 22,323.90, the lowest level since April 16 this year.
The gauge had gained 104.53 points in the previous two sessions.
The broader NSE Nifty of the National Stock Exchange dipped below the crucial 6,700 level and closed at 6,652.55, down by 62.75 points, or 0.93 per cent.
Brokers said sentiment turned weak as selling pressure gathered momentum ahead of outcome of General elections. Slowing down of foreign capital inflows also impacted the market, they added.
A weakening trend in the global markets on escalating tensions in Ukraine added to downward pressure, they said.
IT stocks, mainly Infosys Ltd and TCS, witnessed heavy sell-off after the rupee rose to a one-month high and reports that UBS downgraded Infosys.
Infosys lost 3.15 per cent, Tata Consultancy fell by 1.48 per cent and Wipro by 1.77 per cent.
HDFC fell by 2.75 per cent, Bajaj Auto by 1.60 per cent and Maruti Suzuki by 1.46 per cent.
The IT sector index suffered the most, losing 2.59 per cent to 8,491.49, followed by the teck index which fell 2.23 per cent to 4,734.54.
The realty sector index lost 1.11 per cent to 1,373.54 points and metal index by 0.71 per cent to 9,894.94 and auto index 0.70 per cent to 13,265.53.
Of the 30 Sensex shares, 25 declined, while five ended with gains.