The BSE benchmark Sensex declined by 33 points to 20,216 in late morning trade today on profit-booking by funds and retail investors.The sensex had gained 354.16 points in the previous twosessions. Similarly, the National Stock Exchange index Nifty dipped below the 6,000 mark by falling 8.70 points, or 0.14 per cent, to 5,998.75.