As mentioned in one of the previous post:

A “Special Notified Zone” has been established in the Bharat Diamond Bourse. To facilitate the participation of leading diamond mining companies of the world in this zone, the matter of taxation of income arising from the activity of mere display of uncut diamonds (without sorting or sale) in the Special Notified Zone has been considered by the Government.

It has been decided that the activity of mere display of uncut diamond (without sorting or sale) inside a Special Notified Zone carried out on or after 1st April, 2015 shall not be taxable under the provisions of the Income-tax Act, 1961. Legislative amendment in this regard shall be carried out through Finance Bill 2016.