Markets clawed back, gaining nearly 2% on Tuesday as strength in global equities led confidence. Global markets traded with optimism on reports that the Omicron strain may not be as severe as expected. The BSE Sensex ended at 57,633.65, up 886.51 points or 1.56%. The Nifty was at 17,145.85, up 233.60 points or 1.38%.