BEIJING, Feb. 27 -- The Supreme People's Procuratorate (SPP) is planning an eight-month crackdown on environmental and food safety crimes after detaining a total of 13,495 suspects for such offenses last year.

That number, all of whom were detained with prosecutors' warrants, showed a year-on-year rise of 12 percent, figures from a Thursday press conference showed.

Pollution has become a hot issue for the Chinese public as a week of severe smog in Beijing only ended on Thursday. Meanwhile, cases of food made with shoddy ingredients continue to be discovered on a regular basis.

According to senior SPP official Wan Chun, a nine-month campaign against slack investigation and prosecution was launched in April of last year. It led to thousands of criminal cases related to people's livelihoods being transferred from police and other law enforcement organs to prosecutors.

More than half of these cases involved food safety and environmental issues, while others concerned agriculture, health and education, labor insurance and other fields, Wan said.

In one case revealed earlier by the SPP, a suspect named Liu Liguo sold 100 million yuan's worth of "gutter oil" made from kitchen waste between December 2007 and July 2011. Some 9 million yuan's worth of the unsafe oil entered the market.

Gutter oil contains carcinogenic substances and is dangerous for humans.

Liu was given a life sentence in 2013.

Wan urged investigative supervision offices to go through case records saved by administrative and law enforcement organs within their jurisdictions in order to uncover tips and clues about crimes.

In China, prosecuting organs have the power to supervise the investigation and management of cases by various law enforcement departments including the police and detention centers.