From the Tribeca Jury:

“The best documentary award goes to a film that demonstrates extraordinary mastery of the full symphonic range of cinematic tools: cinematography, editing, score, sound design and, perhaps greatest of all, an exquisite use of metaphor,” the documentary jury said. “To a film that moved us deeply, impressed us immensely and made us feel we were witnessing nothing less than the emergence, fully formed, of a major new cinematic talent, we are thrilled to award the best documentary award to Island of the Hungry Ghosts.”

See more; https://www.hollywoodreporter.com/news/tribeca-film-festival-2018-award-winners-1106265