The Sensex at the Bombay Stock Exchange plunged 231 points, or 1.4 per cent, to 16,645, in opening trade, today, as funds sold heavily, in line with falling global markets. Falling further, the Sensex stood 347 points, or 2.1 percent in the red, at 16,529, a short while ago.Global markets also dropped, as investors nervously eyed the euro's plunge to a near 4-year low against the US dollar, and assessed moves by German financial regulators to ban some types of short selling of euro-zone securities. So the key stock indices in Japan, Hong Kong, Indonesia, South Korea, Singapore and Taiwan were down by between 0.3 per cent and 1.8 per cent. European markets were also trading in the red, today. Over in the US, the Dow Jones Industrial Average has slipped over 1 per cent, overnight.