(2) Except where otherwise provided, this Part shall apply to industrial establishments belonging to or occupied by the State, but in case of any public emergency, the Minister may, by Order published in the Gazette, for the duration of the period specified in the Order, exempt from this part any industrial establishment—
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(a) belonging to or occupied by the State;
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(b) in which work is being carried out on behalf of the State; or
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(c) whose activities are vital to the national interest.