Section 50 ILCS 805/2 - Findings and purpose(a) It is the purpose of this Act to encourage municipalities and counties to protect the land, air, water, natural resources and environment of the State and to encourage the use of such resources in a manner which is socially and economically desirable through the adoption of joint or compatible Local Land Resource Management Plans. The powers granted in this Act are intended to supplement other lawful authority and not to repeal or limit such authority.(b) When a municipality or a county has acted according to this Act, they are furthering the policy of the State in land resource management. It is the intent of this Act for such units of local government to be immune from liability under federal antitrust laws.