Whenever, prior to the enactment of this Act, a tax levy ordinance levying taxes for city and for school purposes has been passed by a majority of a quorum of the members of a city council of a city with a population of less than 500,000 which city operates under special charter (the levy for school purposes having been duly adopted by the Board of Education for such city and duly forwarded to such city council) and a certified copy of such tax levy ordinance has been filed with the County Clerk by the second Tuesday of September of such year and the tax levy ordinance has been ratified by action approved by the majority of the members of the city council (even though such ratifying action has taken place after such second Tuesday of September or after the last day of December of such year) such tax levy is valid and of the same effect as if the tax levy ordinance had been adopted originally by a majority of the members of the city council.