Inside, it detail why North Korea is the #1 suppressor of religion in the world (pg 141) (.pdf)
By all accounts, there are virtually no personal freedoms in the Democratic People’s Republic of North Korea (DPRK or North Korea) and no protection for universal human rights. In pursuit of absolute control of all facets of politics, society, and the flow of information, the government headed by Kim Jong Il has created an environment of fear in which dissent of any kind is not tolerated. Freedom of thought, conscience, and religion or belief does not exist, as the government severely represses public and private religious activities and maintains a policy of tight control over government-sanctioned religious practice. Religious belief of any kind is viewed by the government as a potential competitor to the officially propagated cult of personality centered on Kim Jong Il, and his late father, Kim Il Sung. In the past several years,
North Korean government officials have arrested, imprisoned, tortured, and sometimes executed those discovered engaging in clandestine religious activity. There is no evidence that religious freedom conditions have improved in the past year. The Commission continues to recommend that North Korea be designated a “country of particular concern,” or CPC, which the Department of State has done since 2001.
And this is only the things we do know.