China has been tightening regulations on pollution under a revised law that took effect last year, in a move to protect the environment by introducing harsher punishments and stricter law enforcement, the country's top legislature said.

A report issued on Wednesday by the National People's Congress Standing Committee said that police officers, prosecutors and judges have made significant contributions to the handling of pollution-related cases since the revised law came into effect on Jan 1 last year.

Last year, Chinese public security authorities recorded a total of 6,035 pollution-related cases and arrested more than 12,000 suspects, year-on-year increases of 16 percent and 42 percent respectively, the report said.