Extending its losses for the third straight session, the Sensex at the Bombay Stock Exchange declined 223 points, or 1.2 percent, to 18,210, in line with falling global markets on Thursday. The Sensex has now lost more than 660 points in the last three trading sessions. The Nifty at the National Stock Exchange fell 59 points, or 1.1 percent, to 5,488.Stock markets in Japan, China, South Korea and Singapore dropped between 0.1 percent and 1.5 percent.