Weak cues from global markets also weighed on investor sentiment here, traders said.
After touching a low of 34,499.78, the 30-share index was trading 343.59 points, or 0.99 per cent, lower at 34,525.39.
Similarly, NSE Nifty fell 99.10 points, or 0.96 per cent, to 10,206.20.
Infosys was the top loser in the Sensex pack, shedding around 3 per cent, followed by HDFC Bank, Axis Bank, IndusInd Bank, Asian Paints, ICICI Bank and HDFC.
On the other hand, Bajaj Auto, ITC, NTPC, UltraTech Cement and Reliance Industries were among the gainers.
In the previous session, the BSE barometer closed at 34,868.98, down 561.45 points, or 1.58 per cent, and the broader Nifty tumbled 165.70 points, or 1.58 per cent, to end at 10,305.30.
On a net basis, foreign institutional investors bought equities worth Rs 1,766.90 crore on Wednesday, provisional exchange data showed.
According to traders, expiry of June futures and options (F&O) contracts and border tension with China has added volatility to the market.
Further, rising number of COVID-19 cases in the world is offsetting the optimism over reopening of economies, spooking equity investors globally, they said.
Bourses in Japan and Seoul were trading with losses, while those in Shanghai and Hong Kong were closed for public holidays.
Stock exchanges on Wall Street tanked over 2 per cent in overnight session.
The number of cases around the world linked to the disease has crossed 94.08 lakh and the death toll has reached 4.82 lakh.
India's coronavirus case count stood at 4,73,105, and the death toll rose to 14,894.
Meanwhile, international oil benchmark Brent crude futures fell 0.47 per cent to USD 40.12 per barrel. ANS DRR DRR