Many primary school students in Jiangsu province suffered nosebleeds, dizziness and rashes after attending schools that recently installed plastic running tracks on their playgrounds.

Parents of primary school students in several cities reported similar symptoms that started to show up in their children after school began in September.

The provincial educational department said on Wednesday that schools with pungent plastic tracks must hire professionals to perform tests. It sent a panel of experts to the cities to investigate the bidding process for the construction of the tracks. Any illegal behavior will be severely punished.