The 30-share barometer fell by 30.86 points, or 0.15 per cent, to 20,072.49 with stocks of oil and gas, consumer durable and realty trading in the negative.
The wide-based National Stock Exchange index Nifty declined by 7 points, or 0.12 per cent, to 6,067.80.
Brokers said restricted commitments by participants ahead of the Reserve Bank of India's monetary policy review, to be announced later today, and a weak Asian trend mainly influenced the trading sentiments.
In the Asian region, Japan's Nikkei Index fell by 0.68 per cent, while Hong Kong's Hang Seng index declined by 0.07 per cent in early trade. The US Dow Jones Industrial Average ended 0.10 per cent lower yesterday.
