The Sensex at the Bombay Stock Exchange fell 200 points, or 1.2 per cent, to slip below the 17,000 mark, at 16,885, in opening trade, today, dragged down by fears of an interest rate hike, and weak global markets.Later, after losing more than 330 points at one stage, the Sensex stood 276 points or 1.6 percent in negative territory, at 16,809 a short while ago.Other regional markets in Japan, China, Hong Kong, Indonesia, South Korea, Taiwan and Singapore were down by between 1 percent and 2.4 percent, today, on investor caution ahead of a key European leaders' summit at the weekend. Across on Wall Street, the Dow Jones Industrial Average had slipped 0.6 per cent, overnight.