Awarded a special mention at the 66th Locarno International Film Festival, By The River is the latest feature documentary by Nontawat Numbenchapol. The director, whose previous work Boundary (2013) was at the center of a censorship storm last year, this time transports the audience to the deep forests of Kanchanaburi, in Klity Village, where the Karen locals make their living from a river contaminated with lead due to a nearby factory. Nontawat tells BK about the haunting story behind the visually stunning film.