Earlier, select buying helped the index extend its overnight gains despite trading in a narrow range but the reports of Iraq's sectarian strife and further push by militants to capital Bagdhad amid flare-up in crude oil prices caused volatility in the market.
Barring mild buying in pharma counter, hectic selling was witnessed in banking, energy, FMCG, IT, auto and realty sectors followed by selling in broader indices of mid-cap and small-cap shares.
Meanwhile, foreign portfolio investors (FPIs) bought shares worth a net Rs 48.02 crore yesterday, as per the provisional data from the stock exchanges.
The 50-share Nifty opened lower 7,636.05 and hovered to a high of 7,663.00 and a low of 7,515.50 before concluding at 7,558.20, down 73.50 points, or 0.96 per cent, over its last close.
Major losers were BPCL (down 3.04 per cent), IDFC (2.77 per cent), BHEL (2.60 per cent), Sun Pharma (2.53 per cent) and NMDC (2.45 per cent).
Other losers include DLF, Jindal Steel, Bank of Baroda, TCS and Reliance.
Meanwhile, other Asian markets ended mixed as investors awaited the key US Federal Reserve policy meeting later today.
Turnover in the cash segment climbed to Rs 21,016.97 crore from Rs 18,838.65 crore yesterday.
A total of 13,494.43 lakh shares changed hands in 88,76,069 trades, while the market capitalisation stood at Rs 86,93,739 crore.