As many as 412 students of the junior middle school at Tianshui City of the province participated in the fire and air raid drill on September 18, according to the Tianshui government.
"During the drill, smoke guns were used to simulate a true fire scene. Many students began to cough and vomit after inhaling the smoke," an official statement said.
More than 190 people received medial treatment, state-run Xinhua news agency reported.