Sog Shabdrung, a Tibetan political prisoner, was imprisoned in Nagchu, Drachen District in 1969 during the Chinese government's campaign of political repression. He was reportedly held with approximately 5,000 other prisoners in a newly built prison, where 18 prisoners were confined in a one-square-metre cell without windows for up to four months. Prisoners were subsequently exposed to direct sunlight after prolonged confinement, causing severe eye damage; at least two elderly inmates reportedly became blind as a result.

Sog Shabdrung also reported that conditions in prisons in Sog District were similarly harsh, with around 2,000 prisoners receiving only cold water and being denied access to hot water. His testimony describes systematic overcrowding, inhumane detention conditions, and the mistreatment of Tibetan prisoners during this period.