The Sensex at the Bombay Stock Exchange fell 163 points, or 0.9 percent, to 17,474 in opening trade, this morning, on fresh selling by funds, amid weakness in the regional bourses.Later, selling pressure intensified considerably, and the Sensex had lost as much as 290 points, or 1.6 percent, to 17,347 in afternoon deals, a short while ago.Other Asian markets in Japan, China, Hong Kong, Indonesia, Singapore, South Korea and Taiwan were down by between 0.1 percent and 1.4 percent.