Environment has had a relatively low priority in Turkey. Environmental concerns have been too often superseded by development interest in local decision-making. Strengthened environmental efforts from national government, provincial authorities, and municipalities are required to achieve environmental convergence with the European Union. Despite progress in providing environmental statistics and indicators, the need for integrated studies on environmental sustainability both national and subnational levels is still urgent. The objective of this study is to measure and compare environmental sustainability at sub-national level by using AHP. The proposed model is implemented both the selected sub-regions (NUTS 2 level) and their provinces (NUTS 3 level). In the analysis, SuperDecisions software v.2.2.1 is used and two alternative groups are evaluated according to eleven criteria namely, population density, energy consumption, green area, land use, total disposal, non-treated wastewater, water consumption, number of cars, traffic accidents, SO2 and PM10 emissions. The results indicate that at NUTS 2 level, İstanbul (TR10) the largest city in Turkey with 18% of total population and also one of the most populated cities in Europe is ranked (0.267133) first out of five. İstanbul is followed by regions TR42 Kocaeli, Sakarya, Düzce, Bolu, Yalova (0.189030) and TR41 Bursa, Eskişehir, Bilecik (0.186964) while TR21 Tekirdağ, Edirne, Kırklareli (0.170595) is rated as the least environmentally sustainable region. On the other hand, at NUTS 3 level TR424 Bolu has the highest ranking (0.132935), followed by TR412 Eskişehir (0.121052) and TR413 Bilecik (0.088625). The least environmentally sustainable provinces are TR211 Tekirdağ (0.046646) and TR421Kocaeli (0.037254), respectively. TR100 İstanbul (0.051545) is ranked 11th out of 14.
