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 Central 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 mines situated in the area.
