A refugee is a person who is outside his or her country of origin or habitual residence because they have suffered (or fear) persecution on account of race, religion, nationality, political opinion, or because they are a member of a persecuted 'social group' or because they are fleeing natural disaster. Such a person may be referred to as an 'asylum seeker' until recognized by the state where they make a claim.
As of January 31, 2005, the largest source countries of refugees are Afghanistan, Iraq, Sierra Leone, Myanmar, South Sudan, and the Palestinian Territories. The country with the largest number of IDPs is South Sudan, with over 5 million. As of 2006, with 800,000 refugees and IDPs, Azerbaijan had the highest per capita IDP population in the world.
The 1951 United Nations Convention Relating to the Status of Refugees has adopted the following definition of a refugee (in Article 1.A.2):
[A]ny person who: owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group, or political opinion, is outside the country of his nationality, and is unable to or, owing to such fear, is unwilling to avail himself of the protection of that country".