After the creation of a port authority as provided herein, no municipality within the district shall have power to engage in, or grant any license or permit to any person, firm, corporation or association to engage in, any activities within such municipality which would be competitive with the purpose of the port authority as provided in this act.
The provisions of this section shall not be construed, however, to affect or impair any contracts entered into prior to the creation of a port authority.
N.J.S. § 40:68A-26