President Barack Obama announced Monday evening that he is using his executive power to end solitary confinement for youth incarcerated in federal prisons, adding heft to growing nationwide movements against a practice many consider torture.

In an op-ed article published by The Washington Post, Obama cited deep and long-term psychological harm.

“Research suggests that solitary confinement has the potential to lead to devastating, lasting psychological consequence,” Obama wrote. “It has been linked to depression, alienation, withdrawal, a reduced ability to interact with others and the potential for violent behavior. Some studies indicate that it can worsen existing mental illnesses and even trigger new ones.”

“How can we subject prisoners to unnecessary solitary confinement, knowing its effects, and then expect them to return to our communities as whole people?” Obama posed. “It doesn’t make us safer. It’s an affront to our common humanity.”

In addition to ending solitary confinement for youth, the president said he will also ban the practice “as a response to low-level infractions” and increase “the amount of time inmates in solitary can spend outside of their cells.”

Under the new policies, an incarcerated person can be punished with isolation for a maximum of 60 days for the first infraction–rather than 365 days.

Obama said his decision, which follows an investigation by Attorney General Loretta E. Lynch, will affect “some 10,000 federal prisoners held in solitary confinement.” This number is a fraction of the roughly 100,000 people held in isolation at any given time, up to 25,000 of whom are isolated for months or years, according to the White House’s own figures.

As sweeping as it sounds, the ban on solitary confinement for juveniles applies to just a handful of people. According to the Department of Justice, a small number of youth under the age of 18 are incarcerated in federal prisons. And The Washington Post reports, “Between September 2014 and September 2015, federal authorities were notified of just 13 juveniles who were put in solitary in its prisons.”

Nonetheless, the presidential action appears to constitute a meaningful win for rights campaigners and people incarcerated across the country who have repeatedly demanded an end to solitary confinement and other abuses, including thousands who participated in hunger strikes across the California prison system.

Obama’s announcement comes just months after more than one hundred civil rights and humanitarian organizations sent an open letter to the president calling for the elimination of “long-term and indefinite isolation in the United States.”