SHANGHAI, Aug 18 (Reuters) - China and Hong Kong stocks closed lower on Thursday, hit by increasingly grim growth prospects for the world's second-largest economy, which was dented by COVID-19 outbreaks, a property crisis, a record heat wave and limited room for monetary easing.

** China's blue-chip CSI300 Index dropped 0.9%, while the Shanghai Composite Index lost 0.5%. Hong Kong's Hang Seng benchmark fell 0.8%.

** Nomura lowered its China economic growth forecast, citing dismal July activity data, the lingering impact from the pandemic, and the worst heat wave in six decades.

** "(The) policy response might be too little, too late and too inefficient," said Nomura, which slashed China's growth forecast to 2.9% for the third quarter, from 4.0%. 2023 GDP forecast is also lowered, to 5.1%, from 5.5%, and Nomura expects "a new round of cuts" in coming weeks by other brokerages.

** "Virus outbreaks are happening with increasing frequency. The housing market remains in a downward spiral. And exports look set to drop back before long," wrote Julian Evans-Pritchard, senior China Economist at Capital Economics.

** "More support is on its way but it will probably be too late too little to prevent output from stagnating this year."

** Also, China's central bank faces limited room to manoeuvre due to worries over rising inflation and capital flight, policy insiders and analysts said.

** U.S. Federal Reserve officials steeled themselves to force the economy to slow down with more rate hikes, according to the minutes of the latest policy meeting.

** Increasing divergence in Sino-U.S. monetary policies could trigger capital flight out of China.

** Most sectors in China fell, but the start-up board ChiNext rose 0.3%, while the tech-heavy STAR 50 Index gained 1.3%.

** EVE Energy Co rose 1.2%, after Reuters reported that the Chinese battery maker will supply BMW with large cylindrical batteries for its electric cars in Europe.

** Hong Kong's Hang Seng Tech Index fell 1.1%, but Tencent rose 3.1%, after the Chinese tech giant promised a return to growth, following its first-ever quarterly sales drop. (Reporting by Shanghai Newsroom; editing by Uttaresh.V)