After three years of pledging to stop harvesting organs from deceased prisoners, most of whom have been executed, China has set a a Jan. 1 deadline for ending the common and highly controversial practice.

According to researchers, 90% of Chinese organ transplants from deceased donors come from executed prisoners, who have either been pressured to sign a release form or have their organs taken without permission. (Over half of all organ transplants in China are from deceased donors.) All organs in China are technically supposed to be donated with consent of donors or their families, but many of the transplants take place in on the black market.

The end of forced prisoner donations will be welcomed by human rights advocates. Ethan Gutman, author of The Slaughter, a recent book on the topic, estimates that since the 1990s as many as 65,000 “prisoners of conscience“—including political dissidents, Uighur activists, Tibetan monks and Falun Gong followers—have had their organs harvested after being executed.

But the long awaited policy change will also exacerbate China’s chronic organ shortage. As Quartz has reported, organ donation is unpopular in China because of traditional ideas about death, and also due to worries that donated organs end up being sold by corrupt health officials. The country performed only 2.4 or fewer transplants per one million people in 2012, compared to 75 per million in the US.

Chinese law already states that organ donation requires consent from the donor, but regulation is spotty, which calls into question whether the practice of harvesting organs from executed prisoners will really stop.