(a) City of the first class. A city with a population of one hundred seventy-five thousand or more. (b) City of the second class. A city with a population of fifty thousand and less than one hundred seventy-five thousand. (c) City of the third class. Any city not included in the foregoing classes. (d) The classification herein made shall be determined by the federal census or state enumeration, whichever is the later, as last previously taken before the effective date of this chapter.
New York Legal Code