Mass. Gen. Laws ch. 166, § 22K

If any act required by an ordinance or by-law adopted pursuant to section twenty-two D cannot be performed within the time provided on account of shortage of materials, war, restraint by public authorities, strikes, labor disturbances, or any other circumstances beyond the control of the person obligated to perform such act, then the time within which such act will be accomplished shall be extended for a period equivalent to the time of such limitations.