The 30-share barometer declined by 83.42 points, or 0.40 per cent, to 20,639.55. The index had gained almost 530 points in the last four sessions with metals, banking, power and capital goods sector stocks leading the fall.
Similarly, the National Stock Exchange index Nifty moved down by 32.15 points, or 0.62 per cent, to 6,120.60.
Brokers said besides profit-booking by participants after four sessions of gains, a weak trend in the overseas markets as weak economic data from the US, Japan and China dented investor confidence, mainly influenced the trading sentiments here.
The US Dow Jones Industrial Average ended 0.56 per cent lower in its previous session.