Bloomberg.com reports China's benchmark stock index plunged 7.7% after the government's main business newspaper signaled officials won't try to halt a slump that's erased more than $350 bln of market value in four days. The CSI 300 Index dropped 292.52 to 3511.43, the biggest points slide on record. More than half of the stocks included in the CSI 300 fell by the 10% daily limit, including Huaneng Power International and Air China. Declines were limited to mainland markets. Even after the recent declines, the CSI 300, which tracks yuan-denominated A shares listed on China's two exchanges, is up 72% this year. The Shanghai Composite Index, which tracks the bigger of China's stock exchanges, slid 8.3% to 3670.40. The Shenzhen Composite Index, which covers the smaller one, lost 7.9% to 1039.90.