MEDAN, Indonesia (AP) — Environmentalists have lost a court challenge to a Chinese-backed dam in Indonesia that will rip through the habitat of the most critically endangered orangutan species.

A court in North Sumatra's capital, Medan, ruled Monday that construction can continue despite critics of the 510-megawatt hydro dam providing evidence that its environmental impact assessment was deeply flawed.

Experts say the dam will flood and in other ways alter the habitat of an orangutan species numbering only about 800 primates and likely make it impossible to take a crucial step toward ensuring the species survives — reconnecting fragmented forests the primates are spread across.

Scientists announced the discovery of a third orangutan species, Pongo tapanuliensis, in November. The species is found only in the Batang Toru forest, where the dam will be built.