Snapping its two days of gains, the 30-share BSE Sensex declined 155.77 points or 0.19 per cent to settle at 80,641.07. During the day, it dropped 315.81 points or 0.39 per cent to 80,481.03. The NSE Nifty dipped 81.55 points or 0.33 per cent to 24,379.60.