In this Act references to time of day are references to Indian Standard Time, being five and a half hours ahead of Greenwich Mean Time:
     Provided that for any area in which Indian Standard Time is not ordinarily observed the State Government may make rules--
         (a) specifying the area,
         (b) defining the local mean time ordinarily observed therein, and
         (c) permitting such time to be observed in all or any of the factories situated in the area.