Under Article 15 of the clean air Act, complex buildings, industrial and new-manufacturing centers and units are obliged to allocate at least 10% of the allocated space which is for the related unit construction, to create urban green spaces and plant trees suitable for the region. The operation of these units is subject to compliance with this Article and approval by Iran's Environment Protection Organization (IEPO). It should be noted that according to the classification of the IEPO, various types of electric power generating plants are considered service units because of the nature of these services to the community. Therefore, they are not required to create urban green space. Of course, in case of the water resources availability and land sufficiency, creating urban green space is recommended. (The clean air Act, adopted on July 18, 2017, by the Islamic consultative Assembly, announcement 83/40382 dated August 9, 2017).