Falling for the third straight session, the Sensex at the Bombay Stock Exchange declined 30 points, or 0.2 percent, to close at a three-week low of 19,751, on mild profit-booking by investors, amid some weak quarterly corporate results, and negative European markets, today. The Sensex had risen 121 points at the day's high, and lost 53 points at the day's low. The Nifty at the National Stock Exchange fell 12 points, or 0.2 percent, to 5,987. The broader market took a bigger hit, with the BSE Midcap index losing 0.8 percent, while the Smallcap index declined 0.7 percent.