FIVE YEARS ago, China bid farewell to a brutal relic of Mao’s rule: the laojiao, or reeducation-through-labor camps that had been used since the 1950s to punish minor criminals and all kinds of dissenters, often incarcerating them for up to four years without trial. The National People’s Congress abolished the onerous system on Dec. 28, 2013, because it was seen as obsolete. Now China is reviving forced labor in concentration campsfor Muslim Uighurs in Xinjiang province. This is unconscionable.

It was alarming enough this year to see China’s archipelago of extrajudicial penal colonies take shape. As many as 1.1 million people, or 11.5 percent of the Uighur population of Xinjiang between ages 20 and 79, are captive. China first denied the camps existed, then described them as “transformation through education” facilities needed to prevent extremism, and more recently called them vocational education. But eyewitnesses have described a systematic assault on the language, culture and traditions of the minority Uighur population, forcing them to embrace China’s Mandarin language and Communist Party ideology.

On top of the “reeducation” effort, the New York Times and Financial Times report that China is building factories at the camps, pushing the Uighurs into forced labor, which is regarded as violating a fundamental human right protected by international law and agreements. The New York Times cited commercial registration records that show factories opening in the camps for making textiles, noodles and clothing, as well as printing. In Kashgar, the predominantly Uighur area of southern Xinjiang, plans were made this year to send 100,000 inmates who had been through the job-training centers to work in factories, the report said. The Financial Times cited interviews with the families of detainees, who said they had been employed at textile factories with little to no pay; they are not allowed to leave the factories, and communication with relatives, if permitted, is heavily monitored.