The Sensex at the Bombay Stock Excange gained 88 points, or 0.5 per cent, to 16,794 in opening trade, today, on emergence of buying by funds and retail investors. Later, after showing considerable volatility, the Sensex stood a good 153 points, or 0.9 per cent in the green, at 16,859 in afternoon deals a shortwhile ago.But other Asian markets in Japan, China, Taiwan and Hong Kong were down by between 0.1 percent and 0.8 percent, today, as Spain's financial problems cast fresh a shadow over Europe's economic outlook. The US Dow Jones Industrial Average had ended 0.2 per cent lower in yesterday's trade.