The Sensex at the Bombay Stock Exchange, which had fallen 13 points in opening trade, this morning, later lost further ground, and was down 90 points, or 0.5 percent, at 20,027, a short while ago. The domestic market fell on profit-booking, amid weak global cues.Asian markets in Japan, China, Hong Kong, Taiwan and South Korea were down by between 0.1 percent and 1 percent, today. The US Dow Jones Industrial Average had lost 0.4 percent, overnight.And at the Mumbai foreign exchange market, the rupee weakened 19 paise, to 45.20 against the dollar in early trade, as month-end dollar demand from importers weighed on the rupee.