Macedonians form an overwhelming majority of the population in the municipalities of Aerodrom, Centar, Gjorče Petrov, Karpoš and Kisela Voda, which are all located south of the Vardar. They also form a majority in Butel and Gazi Baba which are north of the river. Albanians form a majority in Čair which roughly corresponds to the Old Bazaar, and in Saraj. They form a large minority in Butel and Gazi Baba. Šuto Orizari, located on the northern edge of the city, is predominantly Roma. When an ethnic minority forms at least 20% of the population in a municipality, its language can become official on the local level. Thus, in Čair and Saraj schools and administration use Albanian, and Romani in Šuto Orizari. The latter is the only municipality in the world where Romani is an official language.