A fall in interest-linked banking, realty and auto stocks mainly influenced the trading sentiment.
Marketmen said investors ignored RBI move to reduce the cash reserve ratio - the percentage of deposits banks keep with the Reserve Bank - by 0.25 per cent to infuse additional liquidity that will inject Rs 17,500 crore into the financial system. CRR now stands at 4.25 per cent.
The Sensex, which had opened with gains on investor hopes of interest rate cuts, fell following the policy announcement to trade at 18,441.26 -- showing a decline of 194.56, or 1.04 per cent at 1151 hrs.
The broad-based National Stock Exchange index Nifty was down by 68.15 points to 5,597.45.