The Sensex at the Bombay Stock Exchange closed with a marginal gain of 17 points, or 0.1 percent, at 17,482, after volatile trade, today. The Nifty at the National Stock Exchange rose 7 points, or 0.1 percent, to 5,266.But stock markets in Hong Kong, South Korea and Singapore lost between 1 percent and 2.5 percent, on continued euro zone worries.