Legal Definitions - citizen suit

A citizen suit is when a person sues someone who has broken the law, especially environmental laws. The person who sues can ask for the lawbreaker to stop breaking the law and also for them to pay a penalty. This is allowed under certain laws, like the Clean Water Act and the Clean Air Act, because sometimes the people who are supposed to enforce the laws don't do it well enough. The idea is that regular people can help protect the environment by suing lawbreakers.

For example, if a company is dumping chemicals into a river and causing harm to the environment, a citizen can sue them to make them stop and pay a penalty. The citizen has to show that they have been harmed by the company's actions and that they have a right to sue under the law.

It's important to note that a citizen can only sue under certain laws and they have to prove that they have been harmed in some way. They can't just sue because they don't like what someone is doing.