15 ILCS 215/2
The Attorney General has the power and authority, notwithstanding and regardless of any proceeding instituted or to be instituted by or before the Environmental Protection Agency, Pollution Control Board or any other administrative agency, to prevent air, land or water pollution within this State by commencing an action or proceeding in the circuit court of any county in which such pollution has been, or is about to be, caused or has occurred, in order to have such pollution stopped or prevented either by mandamus or injunction. The court shall specify a time, not exceeding 21 days after the service of the copy of the petition of mandamus or injunction for answer, and in the meantime the party shall be restrained from continuing such pollution pending hearing before the court. Accompanying such petition shall be a notification to the named defendant that financing may be available, through the Illinois Environmental Facilities Financing Act, to correct the alleged pollution. In case of default, or after answer, the court shall immediately inquire into the facts and circumstances of the case and enter an appropriate order in respect to the matters complained of. An appeal may be taken from the final judgment in the same manner and with the same effect as appeals are taken from judgments of the circuit court in other actions for mandamus or injunction.
15 ILCS 215/2