Benchmark equity indices settled in red on Monday due to profit booking in metal and banking stocks amid mixed trends in global markets. The BSE Sensex settled 523 points or 0.73 per cent lower at 71,072.49. The NSE Nifty also closed 166.45 points or 0.76 per cent lower at 21,616.05. Except for IT & Pharma, all sectors ended in red. PSUs witnessed a heavy profit booking after a sharp rally over the last few months and weak Q3 results posted by many.