Much of Belarus is a hilly lowland, drained by the Dnieper, Western Dvina, and Neman rivers. The climate is moderate humid continental, with warm summers and cold winters. More than one third of the land is covered with peat and other swampy soils, notably in the Pripyat Marshes in the south. In addition to the capital, other important cities are Gomel (in Belarusian, Homyel), Vitebsk (Vitsyebsk), Mogilev (Mahilyow), Bobruysk (Babruysk), Grodno (Horodna), and Brest. Some 80% of the population are Belarusians; Russians, Poles, and Ukrainians are the republic's largest minorities. Since the breakup the USSR, Belarus has experienced a slow decline in population. About 80% of the population belongs to the Orthodox church, and there are Roman Catholic, Protestant, Jewish, and Muslim minorities. Religious groups that have won converts more recently have suffered official discouragement and persecution since independence, a policy that was enacted into law in 2002. Both Belarusian and Russian are official languages, but Russian is more widely used.