A special law enacted pursuant to the provisions of the constitution, article XII, section 2, shall become effective without the approval of any affected local government unit or group of such units in a single county or a number of contiguous counties if the law is in any of the following classes:
(a) A law which enables one or more local government units to exercise authority not granted by general law.
(b) A law which brings a local government unit within the general law by repealing a special law, by removing an exception to the applicability of a general statutory provision, by extending the applicability of a general statutory provision, or by reclassifying local government units.
(c) A law which applies to a single unit or a group of units with a population of more than 1,000,000 people.
A special law as to which local approval is not required shall become effective on August 1 next following its final enactment, unless a different date is specified in the special law.
Subdivisions 1 and 2 are applicable to all special laws enacted and to be enacted at the 1967 and all subsequent sessions of the legislature.