Dystopian fiction is a subgenre of science fiction that explores social and political structures, portraying a future place in cataclysmic decline. It is characterized by elements that are opposite to those associated with utopia, such as deprivation, oppression, terror, and loss of individuality. Dystopian societies are often characterized by fear or distress, tyrannical governments, environmental disaster, or other characteristics associated with a cataclysmic decline in society. Some common characteristics of a dystopian society include propaganda used to control citizens, restricted information and freedom, worship of a figurehead or concept, constant surveillance, fear of the outside world, dehumanization, and uniform expectations. Most dystopian works present a world in which oppressive societal control and the illusion of a perfect society are maintained through one or more types of controls, such as corporate control. Dystopian fiction is usually set in the near future to generate urgency about real current events, and it is by definition science fiction. Dystopian fictions invariably reflect the concerns and fears of their creators contemporaneous culture, and they can be considered a subject of social studies.