The Sensex at the Bombay stock Exchange fell 85 points, 0.5 per cent, to 17,800 in opening trade, this morning, on profit-booking by funds and retail investors, amid weak regional bourses. Later, the Sensex recovered some lost ground, but still stood 43 points, or 0.2 per cent in the red, at 17,842 in afternoon deals, a short while ago. The 30-share Sensex had gained nearly 230 points in the previous two trading sessions.Key stock indices in Japan, China, Hong Kong, South Korea, Singapore, and Taiwan were down by between 0.1 percent and 1 percent, today, after Japan reported a wider-than-expected trade deficit, and as investors await developments from a euro-area finance ministers meeting this week. The US Dow Jones Industrial Average had ended 0.5 per cent lower in yesterday's trade.