The Nifty50 on the National Stock Exchange also plunged over 260 points to trade below the 8,400 mark.
The decline was in line with the global sell-off, as Asian indices fell on the growing number of coronavirus cases worldwide.
At 1.10 p.m., Sensex was trading at 28,792.18, lower by 1,023.41 points or 3.43 per cent from the previous close of 29,815.59
It had opened at 29,226.55 and so far has touched an intra-day high of 29,497.57 and a low of 28,708.83 points
Nifty was trading at 8,396.55, lower by 263.70 points or 3.04 per cent from its previous close.
Although it has been a sell-off across all sectors, banking, financial and auto stocks witnessed heavy selling pressure.
On the Sensex, Bajaj Finance, HDFC, Mahindra & Mahindra, Tata Steel and Maruti Suzuki lost the most while Tech Mahindra, Hindustan Unilever, Nestle India, TCS and Asian Paints were the only gainers.