CAT/C/THA/CO/1 Immigration detention 21. The Committee is concerned at the use of lengthy and, in some cases, indefinite detention in immigration detention centres for asylum seekers and migrants who enter the State party undocumented, as well as at the lack of an independent and systematic review of such detention decisions and the restrictive use of alternatives to detention for asylum seekers (arts. 3, 11 and 16). The State party should review its detention policy with regard to asylum seekers and give priority to alternatives to detention. The State party should end indefinite detention for asylum seekers and migrants and guarantee them access to independent, qualified and free legal advice and representation, in order to ensure that persons in need of international protection are duly recognized and refoulement is prevented. Conditions of detention 22. While acknowledging that the State party has taken a number of measures to improve conditions in detention centres, including the allocation of additional resources to improve the situation of the immigration detention facilities in Songkhla province, the Committee remains seriously concerned at the extremely high levels of overcrowding and harsh conditions prevailing in detention facilities, including immigration detention centres. Such conditions include insufficient ventilation and lighting, poor sanitation and hygiene facilities and inadequate access to health care. The Committee expresses its concern at reports that the lack of medical care has contributed to the spread of diseases and deaths in custody, as in the cases of Rohingya and the Lao Hmong in immigration detention centres, which were raised by the Special Rapporteur on the question of torture and the Special Rapporteur on the right of everyone to the enjoyment of the highest attainable standard of physical and mental health. Reports before the Committee indicate incidents of continuing violence in detention, including sexual violence by prison guards or other prisoners with the acquiescence of the authorities. The Committee also regrets the lack of information about the so-called “white prison” policy, which is alleged to result in further restrictions on the rights and freedom of detainees (arts. 11 and 16). The State party should strengthen its efforts to improve prison conditions in order to end any cruel, inhuman or degrading treatment or punishment, in particular by: (a) Taking all necessary measures to remedy the high rate of prison overcrowding, in particular by instituting alternatives to custodial sentences, in accordance with the United Nations Standard Minimum Rules for Non-custodial Measures (the Tokyo Rules) and the United Nations Rules for the Treatment of Women Prisoners and Non-custodial Measures for Women Offenders (the Bangkok Rules); (b) Ensuring the basic needs of persons deprived of their liberty with regard to sanitation, medical care, food and water. The State party should consider transferring responsibility for health issues in prisons from the Department of Corrections to the Ministry of Health; (c) Taking measures to prevent violence in prison and to investigate all such incidents in order that the suspected perpetrators may be brought to trial and victims may be protected. Use of shacking and solitary confinement 23. While noting that the State party has reviewed and reduced the use of shackles in detention facilities, the Committee expresses concern at: (a) the continued use of instruments of restraint, such as shackles, as disciplinary measures; and (b) the lack of 10