CHONGQING, CHINA - JANUARY 13: (CHINA OUT) A migrant worker erects scaffoldings at a construction site on January 13, 2007 in Chongqing Municipality, China. Economists from Chinese Academy of Social Sciences (CASS) said in the report, 2006-07: World Economy Analysis and Forecast, that it was necessary to keep the interest rate high and real estate cool to avoid the risk of a crisis such as the one Japan weathered in the 1990s. There is at least 30 trillion yuan ($3.75 trillion) in surplus fluid capital on the Chinese market, and this has heated up the real estate sector and the stock market, said Wu Jinglian, a renowned economist with the Development Research Center under the State Council, earlier this week.