(6)Where the Central Government is of opinion that any duty of customs has not been levied or has been short-levied, no order levying or enhancing the duty shall be made under this section unless the person affected by the proposed order is given notice to show cause against it within the time limit specified in section 28.] [Substituted by Act 21 of 1984, Section 43 (w.e.f. 11.5.1984). ]