The 30-share index was trading down by 335.43 points, or 1.34 per cent, to 24,598.90 with all sectoral indices led by metal, capital goods and PSU leading the fall with losses up to 2.29 per cent.
The Sensex had gained 82.50 points in the previous session on Friday.
On similar lines, the NSE Nifty dropped below the 7,500-mark by falling 105.70 points, or 1.39 per cent, to 7,495.65.
Furthermore, the depreciating rupee against the dollar also negatively impacted sentiment in the domestic market, they added.
In the Asian region, Hong Kong's Hang Seng fell 2.61 per cent in early trade, while Shanghai composite index plunged 2.40 per cent. Japan's market remained closed today for a public holiday.
The US Dow Jones Industrial Average ended 1.02 per cent lower on Friday's trade.