The Act applies to all state and local "agencies," which is defined to include (a) every state department, agency, board, bureau, commission, public corporation, and authority; (b) every county, municipal corporation, school district, or other political subdivision of the state; (c) every department, agency, board, bureau, commission, authority, or similar body of each such county, municipal corporation, or other political subdivision of the state; (d) every city, county, regional or other authority established pursuant to law; and (e), with certain exceptions specified in the Act