(b)when a proposal has been sanctioned under sub-section (8) [***] [The word bracket and figure 'or sub-section (3)' were omitted by the Government of Indian (Adaptation of Indian Laws) Order, 1937.] the State Government shall notify the imposition of the tax in accordance with such order or proposal, and shall in the notification specify a date not less than [one month] [Substituted for the words 'Three Months' by Punjab Municipal (amendment) Act, 1952 Punjab Act 23 of 1952).] from the date of notification, on which the tax shall come into force.