The Sensex at the Bombay stock Exchange stood 101 points, or 0.5 per cent in positive territory, at 18,732 in afternoon deals, amid volatile trade, a short while ago. Earlier in the morning, the Sensex had opened with a gain of 27 points, or 0.1 per cent, at 18,658, on selective buying by investors. But other Asian markets in Japan, China, Singapore, South Korea, Taiwan and Indonesia were down by between 0.3 percent and 1.9 percent, today, after a downgrade to Spain's credit rating highlighted Europe's ongoing debt crisis.