the exercise of their right to request the notification of third persons about their stay in the room for detained persons. In 7 Chambers visited by NPM, officers on duty fulfilled the obligation to inform the detained persons about the abovementioned right, while in the remaining 4 Chambers this obligation was not met35.   7.2. Prisons and pre-trial detention centres In 2010, the representatives of the National Preventive Mechanism visited five prisons36, including two establishments as part of repeated visits37, and nine pre-trial detention centres38 (hereinafter referred to as PDC). Figure 4. Number of visits of the National Preventive Mechanism to prisons and pre-trial detention centres in the years 2008-2010.   35 5 9 16 10 30 25 20 2010 r.  2009 r.  15 2008 r. 10 13 16 5 0 Zakłady Karne Areszty Śledcze Pre‐Trial Detention Centres 1. Living conditions Standard Minimum Rules for the Treatment of Prisoners [New York 1984] Rule 11 In all places where prisoners are required to live or work (a) The windows shall be large enough to enable the prisoners to read or work by natural light, and shall be so constructed that they can allow the entrance of fresh air whether or not there is artificial ventilation; (b) Artificial light shall be provided sufficient for the prisoners to read or work without injury to eyesight. Rule 20.1. Every prisoner shall be provided by the administration at the usual hours with                                                              35 Chamber in Kutno – all (2) interlocutors indicated the lack of such instruction; Chamber in Koszalin – 5 out of 6 interlocutors indicated the lack of such instruction; Chamber in Gdynia - the only interlocutor indicated the lack of such instruction; Chamber in Kielce – 1 out of 2 interlocutors indicated the lack of such instruction. 36 Prisons in Tarnów, Czerwony Bór, Hrubieszów, Goleniów, Rzeszów-Załęże. 37 Prisons in Tarnów and Czerwony Bór. 38 Pre-trial detention centres in Choszczno, Środa Wielkopolska, Warszawa-Grochów, Wrocław, Koszalin, Wejherowo, Zielona Góra, Gliwice, Katowice.