The 30-share barometer fell by 120.35 points, or 0.56 per cent, to 21,051.06. The index had lost 155.01 points in previous two sessions.
In a similar fashion, the National Stock Exchange index Nifty declined by 37.30 points, or 0.59 per cent, to 6,271.60.
All the sectoral indices, led by capital goods, auto and banking were trading in the negative zone with losses up to 1.03 per cent.
Brokers said sustained selling by funds amid weak trend in Asian bourses, in line with overnight losses in the US market, mainly influenced the trading sentiment here.
Among other Asian markets, Hong Kong’s Hang Seng index was down 0.55 per cent and Japan’s Nikkei shed 1.61 per cent in morning trade.
The US Dow Jones Industrial Average ended 0.81 per cent lower in yesterday’s trade.