The 30-share index resumed lower at 21,115.00 and hovered in a range of 21,154 to 21,081 before quoting at 21,128.57 at 1030 hours, showing a loss of 5.64 points, or 0.03 per cent from its last close.
The NSE 50-share Nifty also moved down by 3.35 points, or 0.05 per cent, to 6,269.40 at 1030 hours.
Major losers were ONGC (1.76 pct), TCS (1.41 pct), Tata Motors (1.36 pct), Wipro (1.15 pct) and Bajaj Auto (0.96 pct).
Asian stocks fell in their early trade after Federal Reserve Bank of Atlanta President Dennis Lockhart yesterday said the US economy is on solid footing and he would support continued cuts to stimulus.
Key benchmark indices in Hong Kong, Japan, Singapore, South Korea and Taiwan were down 0.11 per cent to 2.05 per cent, while China's Shanghai Composite rose 0.57 pct.
Meanwhile, foreign institutional investors (FIIs) bought shares worth a net Rs 413.85 crore as per provisional data from the stock exchanges.