A file photo shows Changzhou Foreign Language School in east China’s Jiangsu province. [Photo: baidu.com]

A total of 493 students at a middle school in east China's Jiangsu province were diagnosed with medical conditions after the school relocated to a new site.

CCTV News reports that the students were found to have dermatitis or abnormal blood indices, with several among them diagnosed with lymphoma or leukemia.

Pollutants were detected in the underground water and air near the school's new site.

The school is next to an excavation site, where three chemical factories stood.

The detected pollutants reportedly match the chemical discharge from the factories.

Pan Xiaochuan, a professor on public health from Peking University, said the cause must be linked to the pollutants, given so many people were found with similar conditions in a short time.

According to CCTV News, though the school did carry out environmental assessment, the report was done seven months after construction work started at the new campus.

Also, the assessment report was also found to neglect data on some key pollutants related to pesticide.

The school had reportedly suspended classes since January, as a growing number of its students asked for medical leaves.