The indices fell due to weakness in global markets and heavy selling in auto and consumer durable stocks.
The Nift50 on the National Stock Exchange also fell below the psychological mark of 9,000.
At 9.58 a.m., Sensex was trading at 30,516.40, lower by 643.22 or 2.06 per cent from the previous close of 31,159.62.
It had opened at 31,195.72 and has so far touched a low of 30,474.15 points.
The Nifty50 on the National Stock Exchange was trading at 8,931.90, lower by 180.00 points or 1.98 per cent from its previous close.
