Trading on the Shanghai and Shenzhen stock exchanges was ended early on Monday after shares fell seven percent, the first time China's new "circuit breaker" intervened to curb market volatility.
The drop in the CSI300 index, which covers both bourses, for the first time triggered an automatic early closure under the new system, after an initial 15-minute trading halt failed to stem the declines.
The falls followed poor data from official and private surveys of manufacturing in the world's second-largest economy.
In addition, measures introduced to curb China's mid-2015 share slump are about to expire.