An investigatory team on Friday said that dereliction of duty on the part of swimming class instructors was to blame for the Tuesday drowning death of a boy in Shanghai.

Shanghai's sports department, swimming association and life saving association organized the team after a six-year-old boy drowned in a pool on Aug. 21 while participating in a swimming class.

Four of the swimming instructors have been banned from teaching swimmers in the future, while the other instructors have been suspended, the team said.

It was said that the boy's grandfather was responsible for transporting him to the swimming class, although parents and guardians are forbidden from entering the pool while the class is in session.

In July, a five-year-old girl drowned in a hotel in Beijing while attending a swimming class. The deceased girl's mother posted a message on Sina Weibo, a popular microblogging site, asking for the government to create specific rules and regulations to protect children's safety in public pools, as well as to examine and verify the qualifications of teaching instructors.