The Sensex at the Bombay Stock Exchange gained 144 points, or 0.7 per cent to 19,724 in opening trade, this morning, on sustained buying by funds, amid rising Asian bourses. Later, the Sensex remained firm, and stood 150 points, or 0.8 per cent per cent in the green, at 19,731 in afternoon deals, a short while ago.Key stock indices in Hong Kong, Singapore, South Korea, Taiwan and Indonesia were up by between 0.7 percent and 2.1 percent, today, after the US House of Representatives yesterday voted to pass a bipartisan deal to stave off a fiscal cliff of drastic taxation and spending measures.