Quarantine authorities nationwide uncovered 208 instances in which excessive levels of radiation were found in imported cargo containers in September, the nation's top quality watchdog said on Thursday.

There was 19.6 percent more radiation from the same period last year, said Chen Xitong, spokesman for the General Administration of Quality Supervision, Inspection and Quarantine.

A figure provided by the authority shows that more than 1,000 cargo containers were found with excessive levels of radiation in the first half of this year. Last month, customs in Taizhou, Zhejiang province, seized 952 metric tons of waste materials that were imported from Japan.