Mamutjan, a Uyghur teacher who was imprisoned in 2015 for an irregularity in his travel documentation, says he was beaten for failing to meet the high tomato quotas expected of him.

“In a dark prison cell, there were chains hanging from the ceiling. They hung me up there and said ‘Why can’t you finish the job?’ They beat my buttocks really hard, hit me in the ribs. I still have marks.”