Recovering only partially from early losses, the Sensex at the Bombay Stock Exchange stood 21 points, or 0.1 percent in negative territory, at 17,581 in afternoon deals, a short while ago. Earlier in the morning, the Sensex had lost 52 points, or 0.3 per cent, at 17,550, on profit-booking by investors, amid largely subdued regional markets.Other regional stock indices in China, Hong Kong, South Korea and Singapore fell slightly, after a private survey showed that China's manufacturing sector activity shrank in March. Over in the US, the Dow Jones Industrial Average had dropped 0.4 per cent, overnight.