Indian markets ended flat to negative on Tuesday erasing earlier gains. At the close, the 30-share benchmark index, BSE Sensex ended flat with a decline of 24.48 points or 0.08% at 32,609.16 with 17 components registering drop. while the broad based NSE Nifty closed flat with a gain of 3.60 points or 0.04%, at 10,234.45 with 24 components registering rise.