Benchmark equity indices, the BSE Sensex and NSE Nifty50, closed lower on Thursday, reflecting a downturn amid the expiry of Nifty50 contracts and following trends seen in Asian markets. The BSE Sensex dropped by 494.75 points, or 0.61%, finishing at 81,006.61. Similarly, the NSE Nifty50 closed at 24,749.85, down 221.45 points, or 0.89%.