(a) Whenever used in the text of this section, the following words and terms shall have the following meanings:—

''Full and fair cash valuation'', the fair cash value of all real estate and personal property as defined in this chapter, as certified by the commissioner, or, if no certification has been made, as last reported by the commissioner to the general court pursuant to section ten C of chapter fifty-eight as updated by the commissioner for any intervening period by an appropriate factor, if any.

''Local appropriating authority'', in a town, the board of selectmen; in a city, the council, with the mayor's approval when required by law; in a municipality having a town council form of government, the town council.

''Total taxes assessed'', the net amount to be raised by any ad valorem tax levied on the real estate and personal property located within a city or town.

(b) The total taxes assessed within any city or town under the provisions of this chapter shall not exceed two and one-half per cent of the full and fair cash valuation in said city or town in any fiscal year. Any city or town in which total taxes exceed this limit shall be subject to the provisions of paragraph (d).

[There is no paragraph (c).]