Erasing all its initial gains, the Sensex at the Bombay Stock Exchange declined 255 points, or 1.6 percent, to slip below the 16,000 level, at 15,959 in afternoon deals. Stocks fell after the latest data showed that industrial output contracted 5.1 percent in October.Earlier in the morning, however, the Sensex had risen 147 points, or 0.9 per cent, to 16,360, on fresh buying by investors, amid firm regional bourses. The 30-share Sensex has already lost over 660 points in the past two trading sessions. Other Asian markets in Japan, Hong Kong, Indonesia, Singapore, South Korea and Taiwan were up by between 0.5 percent and 1.5 percent, as investors welcomed a new European fiscal pact aimed at fixing the region's debt crisis and preventing a collapse of the euro.