In highly volatile trade, the BSE benchmark Sensex pared over 200-point gain on Thursday to close the day 91 points down at nearly four-month low levels on emergence of fag-end selling amid new political developments and weak global cues.
Falling for the fifth straight day, the Sensex fell by 91.32 points, or 0.48%, to 18,792.87, its lowest level since November 26, 2012. The index had lost 686 points in last four sessions.
The broad-based National Stock Exchange index Nifty fell by 35.65 points, or 0.63%, to 5,658.75 led by stocks of realty, power and capital goods.
Brokers said trading sentiment turned bearish ever since DMK withdrew its support to the ruling UPA government, raising concerns that economic reforms pace might get derailed.
CBI carried out raids at the residence of DMK chief M Karunanidhi's son M K Stalin on Thursday, two days after the party pulled out of UPA, triggering a political controversy over its timing with even top central ministers strongly disapproving of the action.
"Concern over economic and political health of the country has revived worries and selling is seen on rallies," said Nidhi Saraswat, senior research analyst, Bonanza Portfolio Ltd.
They said a mixed trend in the Asian region and lower opening in Europe on deepening Eurozone debt crisis further influenced the market sentiment.
In 30-BSE index components, 19 stocks declined led by Bajaj Auto, BHEL, Cipla, Dr Ready, HDFC Bank, Larsen and Toubro, Tata Motors, Maruti Suzuki, Reliance Industries, Tata Power and Tata Steel.
Bucking the general weakening trend, ICICI Bank, Bharti Airtel, HDFC Bank, SBI, Infosys and Jindal steel gained and capped the losses to some extent.
The realty sector suffered the most by losing 2.91% to 1,804.95 followed by power index by 2.38% to 1,633.25. Capital goods fell 2.30% to 9,112.80 and auto index by 2.23% to 10,114.98.