Chinese authorities in Tibet have denied to retry an envirnomental activist who is serving a seven-year sentence for campaigning against government corruption, his lawyer said on social media.

Anya Sengdra, 53, a resident of Kyangchu township in Gade (in Chinese, Gande) county in the Golog (Guoluo) Tibetan Autonomous Prefecture has already served six years of his sentence for “disturbing social order” after he complained online about corrupt officials, illegal mining and the hunting of protected wildlife.

He was convicted and sentenced in 2019, and has attempted to appeal the decision twice before, his lawyer Lin Qilei said in a post on X on Tuesday.

“This marks the third appeal for a retrial submitted to the Sixth Circuit Court of the Supreme People’s Court in Xi’an,” Lin said on X.

“As usual, I filled out the necessary forms and waited in line. After some time, a judge came out and informed me that they had decided not to review Sengdra’s case,” Lin said. “He advised me not to return to the court regarding this matter in the future.”

In 2020, a group of UN human rights experts appealed to the Chinese government, urging them to dismiss the charges against him.

Earlier this month, the Chinese authorities detained Tsogon Tsering, a Tibetan environmental activist from Sichuan province after he made a rare public appeal on social media for action against a company he accused of illegally extracting sand and gravel from a river.

Tsering has remained in custody since then and his whereabouts are still unknown.