Under the proviso to Section 17(1) of the Patents Act, 1970, an application shall not be post-dated to…

The proviso to section 17(1) bars post-dating "to a date later than six months from the date on which it was actually made or would, but for the provisions of this sub-section, be deemed to have been made". Twelve months is the period for completing a provisional specification and eighteen months the period for publication, neither of which applies here.