Indian equity indices ended on a weak note with Nifty below 25,000 on July 18. At close, the Sensex was down 501.51 points or 0.61 percent at 81,757.73, and the Nifty was down 143.05 points or 0.57 percent at 24,968.40. About 1619 shares advanced, 2265 shares declined, and 153 shares unchanged.