Growth in Chinese manufacturing activity slowed in August, two closely watched surveys showed yesterday, losing momentum as a declining property sector and waning stimulus effects weigh on the world's second-largest economy. The official purchasing managers index (PMI) came in at 51.1 last month, the National Bureau of Statistics said in a statement. The figure was down from 51.7 in July, and the first decline since slipping to 50.2 in February, according to previous data. Readings above 50 indicate growth, while anything below points to contraction.Separately, British bank HSBC announced a fall in its own survey to a final reading of 50.2 for August, down from an 18-month high of 51.7 in July and its lowest level in three months. The indices track manufacturing activity in China's factories and workshops and are closely watched indicators of the health of the economy. The official August figure came in just above the median 51.0 forecast in a survey of 10 economists by Dow Jones Newswires. July's result had been the best since 53.3 in April 2012. Analysts said the result indicated China's economic recovery was being stunted by problems in the property sector - where new house prices posted their fourth consecutive month-onmonth decline - as well as the weakening impact of stimulus measures taken to boost growth. "The weak PMI data suggests that China's shallow growth recovery has started to lose momentum, likely because of the ongoing property market correction and a decline in the efficacy of policy easing due to structural problems in the economy," economists at Nomura International said in a report.China's economic growth accelerated to a higher-than-expected 7.5 percent in the second quarter, up from 7.4 percent in the previous three months.That was the worst since a similar 7.4 percent expansion in July-September 2012. Authorities have since April launched a series of measures to bolster growth, including tax breaks for small enterprises, targeted infrastructure outlays and incentives to encourage lending in rural areas and to small companies.