Snapping a two-day rally, the Sensex at the Bombay Stock Exchange closed with a modest loss of 38 points, or 0.2 percent, at 17,847, amid weak Asian and European markets on Wednesday.The Sensex had gained almost 230 points in the last two trading sessions. The Nifty at the National Stock Exchange fell 8 points, or 0.2 percent, to 5,413.Stock markets in Japan, China, Hong Kong, South Korea and Singapore dropped between 0.3 percent and 1 percent.