Colombian energy giant Ecopetrol has polluted hundreds of sites with oil, including water sources and biodiverse wetlands, the BBC World Service has found.

Data leaked by a former employee reveals more than 800 records of these sites from 1989 to 2018, and indicates the company had failed to report about a fifth of them.

The BBC has also obtained figures showing the company has spilled oil hundreds of times since then.

Ecopetrol says it complies fully with Colombian law and has industry-leading practices on sustainability.

The company's main refinery is in Barrancabermeja, 260km (162 miles) north of the Colombian capital Bogota.

The huge cluster of processing plants, industrial chimneys and storage tanks stretches for close to 2km (1.2 miles) along the banks of Colombia's longest river, the Magdalena – a water source for millions of people.