(b)when such building or land has remained vacant and unproductive of rent, in respect of any time, not being less than sixty consecutive days during which within the season, the Chief Executive Officer shall remit or refund one-half of such portion of any tax assessed on the annual rateable value thereof as bears to the whole of the tax so assessed the same proportion as the number of days during which the building or land has remained vacant and unproductive of rent bears to the total length of the season.
