In the film, the Progress Corps is a thinly-veiled reference to the US Peace Corps. After the film's release, the Peace Corps was expelled from Bolivia in 1971. Reports that they had sterilized poor Bolivians were fiction but the film created enough controversy to warrant kicking them out.
The Quechua-speaking Indians of this Andean community were initially hostile to the filmmakers until a coca-leaf divination ritual confirmed the filmmakers' good intentions.
Mules had to be used to transport the filmmakers and their equipment to a high and remote Indian community where parts of the film were shot.
The Bolivian government, allegedly at the insistence of U.S. officials, initially banned the film. After 24 hours, the ban was lifted due to public pressure generated by widespread protests and demonstrations. It became a critical success and favorite of Bolivians for its socially significant themes.