A public nuisance is something that threatens the health, safety or comfort of members of the public.
Examples of public nuisances include keeping wild animals such as bears on one's property, lighting off fireworks on crowded streets, polluting ponds or rivers, and a number of other similar offenses.
Public nuisances are generally considered to be minor crimes. They can be accompanied by fines. However, if they are serious enough, then further punishment can be associated with them.
Public nuisances are also different from private nuisances. The latter typically applies to neighbors and does not impact the general public. For example, a person practicing a loud electric guitar at 3 a.m. in the morning may be a private nuisance to their neighbors.