Of the 118 arrests, 24 people have been charged by prosecutors and await trial, the ministry said in a statement.
The ministry began a national campaign against environmental polluters earlier this year, and as part of that campaign, they said they've had major breakthroughs in some of the cases, the official Chinese news agency Xinhua reported.
Most of the cases involve mining or petrochemical factories accused of discharging toxic substances into the environment illegally, Xinhua said. Others allegedly used illegal middlemen to sell the toxic waste to companies or individuals who were not qualified to process the waste, the ministry statement said.
Some of the polluters had gained support from local governments because they are big taxpayers, the statement added.
Meanwhile, China's supreme court and procuratorate jointly issued a new judicial explanation Tuesday making it easier to investigate cases of environmental pollution, Xinhua said.