The Court of Arbitration said the partial award is
"final" with respect to the matters decided by it. The award is binding on the two countries.
It clarified that the ruling does not apply to plants already in operation or under construction, whose designs have been communicated by India and not objected to by Pakistan.
The award is regarding the legality of construction and operation of the hydro-electric project by India and the permissibility under the treaty of the depletion of the reservoirs of certain Indian hydro-electric plants below "dead storage level".
On Pakistan's demand to direct India to stop diverting water, the court observed that the treaty expressly permits the transfer of water by India from one tributary of the Jhelum to another for the purpose of generating hydro-electric power, subject to certain conditions.
It found that KHEP's inter-tributary transfer is "necessary", as required by the treaty, for the generation of hydroelectric power.
It said power can be generated on the scale contemplated by India in this location only by using the 665 m difference in elevation between the dam site on the Kishenganga/Neelum and the place where water is released into the Bonar Nallah.
However, the court also decided that India's right to divert the Kishenganga/Neelum water is not absolute and Pakistan retains the right to receive a minimum flow of water from India in Kishenganga/Neelum riverbed at all times.
The court noted that this right also stems from customary international environmental law, and that it considered that the Treaty must be applied in light of contemporary international environmental law principles.
The court made it clear that the award will not have any bearing on any territorial claims or rights of countries over Jammu and Kashmir. "The court's findings pertain solely to the parties' rights and obligations with respect to the use of the waters of the Indus system of rivers...," it said.
The seven-member Court of Arbitration is chaired by judge Stephen M Schwebel of the US who is former president of the International Court of Justice. The other members of the court are Franklin Berman and Howard S Wheater (UK), Lucius Caflisch (Switzerland), Jan Paulsson (Sweden) and judges Bruno Simma (Germany) and Peter Tomka (Slovakia).