Courts in China's eastern Zhejiang province heard 492 cases relating to environmental crimes in 2015, one third of the national total of this crime type, a report released today said.

In 2015, the records of 1,322 cases in their first trial related to environmental contamination were released on the official legal documents website.?Among the provinces, Zhejiang ranked first, according to a report targeted on environmental contamination crimes.

Following Zhejiang, courts in Hebei in North China heard 263 criminal cases and Shandong in East China heard 164 cases, the report said.

Based on the released records, Beijing and six provinces, such as Qinghai and?Jilin, heard no such cases in 2015.

It's the first report targeting environmental contamination crimes, since it was officially added to the list of crimes and implemented in June 2013.

The report was co-conducted by the China Biodiversity Conservation and Green Development Foundation, an environmental organization based in Beijing, and the Environmental Defense Fund, a US green NGO, which based it on the records on the website and a three-month field investigation in some provinces.?

There were more environmental pollution crimes actually heard in 2015 than the number released on the website, since some courts did not publish their records as required, Yan Houfu, an environmental researcher at Beijing Normal University and the report's major author, said on Thursday.

Among the 1,322 released cases?in their first trail last year, only one defendant was found not guilty, the report said.

The accused were found guilty in the remaining 1,321 cases. The cases showed clear trends that over half of the polluters were accused for excessively discharging toxic pollutants three times higher than the national standards on such pollutants' emissions.

"Besides, some provinces have conducted stricter enforcement on environmental crimes than other regions, meaning some polluting companies escaped to other provinces to avoid legal punishments," Yan said.

In addition, from the records and field investigations, they found the defendants did not get the strict punishment the laws stipulated.

Thus the research team suggested the local governments adopt the unified standards in punishing the polluters and intensify the crackdown by using the laws and regulations to deter polluters.