Shanghai shares nosedived 8.49 percent on Monday as Beijing's latest market intervention failed to restore confidence, with concern mounting about the stalling economy.

The benchmark Shanghai Composite Index closed down 297.83 points at 3,209.91, after falling as much as 9.00 percent during trading. The Shenzhen Composite Index, which tracks stocks on China's second exchange, plunged 7.70 percent, or 156.94 points, to 1,882.46 on turnover of 272.9 billion yuan.