740 ILCS 174/40: Home Rule Limitation.

It is the public policy of this State, pursuant to paragraphs (h) and (i) of Section 6 of Article VII of the Illinois Constitution that the provisions of this Act are the exclusive exercise by the State of powers and functions which might otherwise be exercised by other home rule units. Such powers and functions may not be exercised concurrently, either directly or indirectly by any unit of local government, including any home rule unit except as otherwise authorized by this Act.