The 30-share index, which had gained 669.08 points in the previous five sessions, fell by 104.89, or 0.49 per cent, to 21,134.47.
All the sectoral indices led by Informational Technology and Banking stocks were trading in the negative zone with losses up to 1.21 per cent.
Similarly, the National Stock Exchange index Nifty moved down by 30.20 points, or 0.48 per cent, to 6,287.15.
Brokers said selling, mostly of a profit-booking nature, by funds after five sessions of gains amid a mixed trend at other Asian bourses, mainly influenced the trading sentiment.
In the Asian region, Japan’s Nikkei Index was down 0.16 per cent, while Hong Kong’s Hang Seng index was up 0.53 per cent in early trade.