The Sensex at the Bombay Stock Exchange fell 191 points, or 1.2 per cent, to 16,180 within the first five minutes of trade, this morning, as investors continued to offload stocks amid falling regional bourses. Later the Sensex remained weak, and stood 190 points, or 1.1 percent in negative territory, at 16,181, in afternoon deals, a short while ago. The 30-share Sensex has already lost almost 1,200 points in the past seven trading sessions.Other Asian bourses in Japan, China, Hong Kong, Indonesia, South Korea, Taiwan and Singapore were down by between 0.4 percent and 2.4 percent, as investors fretted about European and US debt problems.