Sensex fell 119 points to 81,785.74, Nifty dropped 44.80 points to 25,069.20, snapping an eight-day winning streak.
Profit-taking in IT and auto shares ahead of the US Federal Reserve policy meeting drove the decline.
Sensex laggards included Mahindra & Mahindra, Infosys, Asian Paints, Titan, Sun Pharma, TCS, Tech Mahindra, and Power Grid.
Gainers included Bajaj Finance, UltraTech Cement, Reliance Industries, and Eternal.
Broader markets showed smallcap +0.66% and midcap +0.40%.