The Sensex at the Bombay Stock Exchange fell 56 points, or 0.3 per cent, to 17,575 in early trade, today, on sustained selling by funds and retail investors, amid mixed regional bourses. Later, the Sensex lost some more ground, and stood 124 points, or 0.7 percent in the red, at 17,507 in afternoon deals, a short while ago. The 30-share Sensex had lost nearly 220 points in the previous three trading sessions.Key stock indices in Japan, China, South Korea, Taiwan, Hong Kong, and Indonesia were trading mixed, today. The US Dow Jones Industrial Average had ended 0.2 per cent lower in Tuesday's trade.