China's main stock index plunged 8.3 percent on Monday in its biggest one-day drop since a February drop that triggered a global market sell-off. The Shanghai Composite Index fell sharply for a second day, tumbling 8.3 percent to 3,670.40, after a 2.7 percent decline Friday. The Shenzhen Composite Index for China's smaller second market fell 7.9 percent to 1,039.90. The declines came after the Chinese government last week raised a tax on stock trading in an effort to cool a market boom that authorities worry could create a dangerous price bubble, the Associated Press reported.
