A key stock market index in Hong Kong saw the biggest single-day drop since the financial crisis on Tuesday. The Hang Seng index fell by -2172.99 (-9.41 percent) on Tuesday. The drop followed an announcement on Tuesday by China's economic planning agency that outlined details of measures aimed at boosting the economy but refrained from major spending initiatives.

The CSI 300 Index pared gains after registering a record intraday jump while the Hang Seng Index slumped the most since 2008.

China is back to work after the fall "Golden Week" holiday, and the sheen is coming off a recent market rally. A briefing from the country's top economic planner, the National Development and Reform Commission,