The Justice Department is set to release about 6,000 inmates early from prison — the largest one-time release of federal prisoners — in an effort to reduce overcrowding and provide relief to drug offenders who received harsh sentences over the past three decades.

The inmates from federal prisons nationwide will be set free by the department’s Bureau of Prisons between Oct. 30 and Nov. 2. Most of them will go to halfway houses and home confinement before being put on supervised release, the Washington Post reports.

The early release follows action by the U.S. Sentencing Commission — an independent agency that sets sentencing policies for federal crimes — which reduced the potential punishment for future drug offenders last year and then made that change retroactive.

The panel estimated that its change in sentencing guidelines eventually could result in 46,000 of the nation’s approximately 100,000 drug offenders in federal prison qualifying for early release. The 6,000 figure, which has not been reported previously, is the first tranche in that process.

The Sentencing Commission estimated that an additional 8,550 inmates would be eligible for release between this Nov. 1 and Nov. 1, 2016.