- 17 The situation was also acceptable in certain parts of Athens (e.g. 3rd and 11th floors), Kozani (Security Department) and Piraeus Police Headquarters. The Traffic Police cell at the Kozani Headquarters would also have offered good conditions of detention, had it not been for the fact that it was devoid of all lighting. However, in several of the above-mentioned establishments, certain cells measured a mere 3.5 m². As indicated in previous visit reports (cf. CPT/Inf (2001) 18, Part I, paragraph 26), cells of such a size are only suitable for temporary holding purposes (i.e. for a maximum of a few hours); they should not be used to accommodate detained persons overnight. 25. Detained persons did not fare as well in other parts of Athens Police Headquarters (7th floor), in Khania and Igoumenitsa Police Headquarters, at the Heraklion Security Department and in Chersonissos and Drapetzona Police Stations. The premises were unhygienic and in a poor state of repair, and the available mattresses and blankets were dirty. While the Heraklion Port Police did not have detention facilities, much needed renovation work had just begun at Piraeus Port Police Station. 26. At Kypseli Police Station, the delegation found that the cells were filthy, poorly lit and ventilated, and overcrowded; e.g. three persons were being held in a 3.6 m² cell and four in a 6.8 m² cell. Most of the persons met had been detained at the police station for a few hours (for identification purposes). However, the CPT is very concerned to note that three of them had been held in those facilities for two weeks or more. 27. Conditions of detention in the Police Station at the Kozani Police Headquarters and in the Heraklion Police Headquarters were also wholly unacceptable. The cells in the Police Station at the Kozani Police Headquarters were severely overcrowded (e.g. nine persons were being held in 10 m²), had no access to natural light, and were insufficiently lit and ventilated; they were also in a poor state of hygiene and repair. Further, not all persons detained had their own mattress. The cells were equipped with a washbasin and a lavatory; however, the lavatories had no partitioning. The Heraklion Police Headquarters had a dungeon-like detention facility in the basement of the court house. The cells had no access to natural light, artificial lighting was generally dim and ventilation poor; the premises (including sanitary facilities) were filthy and their state of repair also left a lot to be desired. The detention facility was overcrowded (e.g. four persons to a 9.5 m² cell). Further, not all detainees had been provided with mattresses, and the items which were available were extremely dirty and worn out. The CPT is particularly concerned that some immigration detainees had been held under such conditions for several weeks. Kozani and Heraklion Police Headquarters were the subject of an immediate observation under Article 8, paragraph 5, of the Convention (cf. paragraph 8).