Meant to placate the anger of Indian masses. Your foriegn ministry used the word "Abeyance" and not cancellation, because it cant be legally cancelled unilaterally.
Arunachal Pradesh, Assam, and other northeastern states are highly dependent on the Brahmaputra for agriculture, drinking water, and hydropower.China could also block tributaries of ganges.
China already is building massive dams in tibet . Infact Medog will be the worlds largest dam (60,000 MW) . On the otherhand ,it would take India a decade to complete the infrastructure to divert Chenab, Jhellum and sutlej.