The 30-share index resumed lower at 20,073.41 and hovered in a range of 20,109.08 and 19,967.12 before quoting 19,990.07 points at 1030 hours.
It showed a loss of 132.25 points or 0.66 per cent from Friday's closing level.
The NSE 50-share barometer Nifty also moved down by 40.60 points or 0.66 per cent to 6,066.65 at 1030 hours.
Major losers were - ITC (2.57 per cent), TCS (2.13 per cent), BHEL (1.40 per cent), Infosys (1.28 per cent), HDFC (1.10 per cent) and Larsen & Toubro (1.04 per cent).
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Key benchmark indices in China, Hong Kong, Indonesia, Singapore and Taiwan fell by 0.18 to 1.02 per cent while South Korea's Kospi rose 0.03 per cent.
Japanese stocks jumped to their highest level in more than five years, boosted by an improved profit outlook and further yen weakness after the Group of Seven major economies refrained from criticising Tokyo's easing policies.