The Central Government may, to enable more efficient use of spectrum, re-farm or harmonise any frequency range assigned under section 4, subject to such terms and conditions, as may be prescribed.

   Explanation.—For the purposes of this section,—

   (a)  “harmonisation” means rearrangement of a frequency range;

   (b)  “re-farming” means repurposing of a frequency range for a different use, other than that for which it is used by an existing assignee.