Opening with unearthly looking shots of Venezuela’s hulking oil refineries, this strikingly photographed documentary is a lament in response to the political and humanitarian crisis the country has faced in the last decade. As per the title, director Álvaro F Pulpeiro has a habit of looking frequently to the skies, casting them in an aghast, high-contrast yellow and indigo, as if the spillage of this petrostate’s woes has tainted something spiritual in the higher order of things.

Interspersing it all with radio commentary discoursing on million per-cent inflation and the disputed 2018 election, and poetry extracts tolling the bell for the country itself, Pulpeiro roams Venezuela in search of telling vignettes: soldiers firing ordnance off navy vessels in the Caribbean, refugees joining the exodus into Brazil, a recurring ride-along with a man transporting a newborn child (a symbol of hope, or maybe hopelessness).

Only once – as a mariachi group serenades a pair of giggling women in the back of a pickup truck – is there much optimism. Otherwise, the pervasive mood is a sense of betrayal by those in power. At one point, driving around as the baby wails in the backseat, the radio relays Venezuelan president Nicolás Maduro denouncing Donald Trump, and Pulpeiro owns them both with another burst of verse: “I’m talking to you as a child from a homeland just like any other / A father like any other / Voracious Saturn.”

That Venezuela is devouring its children hits home in the long final section, accompanying a group of almost Mad Max-like wastrels decanting gasoline in rough conditions at a makeshift depot in the Guajira desert just across the border in Colombia. So Foul a Sky loses some of its rhythm and lyrical bite in this rather baggy and meandering segment, which accounts for almost a third of the runtime. But it’s a courageous expedition into a bitumen-stained heart of darkness.

• So Foul a Sky is available on True Story from 28 July.