If at any time between each decennial federal census, a city annexes or detaches territory or consolidates with another city, the city council of the city annexing or detaching the territory or the city council of the successor city, shall reexamine the boundaries of its council districts, if any, after the first census is taken or after the population estimates are obtained, following the annexation, detachment, or consolidation.
If, upon reexamination, the city council finds that the population of any council districts have varied so that the districts no longer meet the criteria specified in Section 21601 of the Elections Code, the city council shall, within 60 days after the census is taken, or population estimate received, by ordinance or resolution, adjust the boundaries of any or all of the council districts of the city so that the districts are as nearly equal in population as may be possible.