For decades the Black Sea has been treated as a dumping ground for agricultural and industrial waste from south eastern Europe – with things so bad that scientists considered parts of it almost entirely dead.
But what has been done to turn things around and is there any prospect of an improvement?
The BBC’s Jonah Fisher travelled across the region, trying to find out if there’s any chance of the Black Sea cleaning up its act.
Video produced by Abdujalil Abdurasulov