The urea content in nearly 10 percent of swimming pools in China exceed the safe limit, according to a recent report released by the Health Ministry after it inspected 5,639 swimming pools in 24 Chinese provinces, municipalities and regions between June and August, Beijing Times reported on Sunday.

According to the report, only 90.8 percent of swimming pools meet the national standard of urea content in swimming pools and 83.7 percent meet the standard for residual chlorine content.

The report also shows 13.7 percent of disinfected ponds contained excessive amounts of residual chlorine.

The pass rate of the total number of bacteria in swimming pool water can reach 92.3 percent and the rate of coli bacteria can reach 96.9 percent, the report said.

According to the report, the main reason for the over-standard of urea is the water circulation does not work well and refilling water and the frequency of water filling are not enough.

The over standard of residual chlorine is mainly for unscientific use of disinfectants.

The Health Ministry urges local departments to supervise swimming pool operators to improve the facilities that don't meet the national standard in order to keep the water quality in the swimming pools.