It is possible for a person to have no nationality, according to the United Nations High Commissioner for Refugees. People can be born without a state or become stateless over the course of their lives. Statelessness is caused by discrimination and problems with nationality legislation.
Changes in citizenship laws sometimes result in large segments of people no longer being recognized as citizens of that nation, explains the UNHCR. Periods of war and mass migrations of ethnic groups, such as in situations to escape persecution, sometimes create conditions of statelessness. As of March 2015, an estimated 10 million people around the world have no nationality.