25. This Ordinance shall not, unless the Government by notification in the official Gazette otherwise directs, apply-(a) to an undertaking which is owned by the ¹[Government], or(b) to an undertaking which is owned by a body corporate established by the Government by law or whose Chief Executive is appointed by or with the approval of the ²[Government], or(c) to anything done by any person or undertaking in pursuance of any order of the ³[Government], or(d) to anything done by a trade union or its members for carrying out its purposes.