The Convention Relating to the Status of Refugees, adopted in 1951, is the primary international treaty that defines the rights of refugees and sets out the obligations of states to protect them.

According to the 1951 Refugee Convention, a refugee is a person who has been forced to leave their country due to persecution based on race, religion, nationality, political opinion, or membership in a particular social group.

De jure statelessness occurs when a person is not considered a national of any state under the law. De facto statelessness occurs when a person is unable to prove their nationality, even though they may be considered a national of a state under the law. Habitual residence statelessness occurs when a person has lived in a country for a long period of time but is not considered a national of that country.

The Convention on the Reduction of Statelessness, adopted in 1961, is the main international treaty that sets out the rights of stateless persons and the obligations of states to prevent and reduce statelessness.

Discrimination, conflict, and natural disasters are the main causes of statelessness. Discrimination can lead to the denial of nationality, conflict can lead to the destruction of nationality documents, and natural disasters can lead to the loss of nationality documents.

Statelessness can lead to a lack of access to basic services, such as education, healthcare, and social security. It can also lead to discrimination and poverty, as stateless persons are often denied the same rights and opportunities as nationals.

Stateless persons face a number of challenges, including lack of legal protection, discrimination, and poverty. They are often denied the same rights and opportunities as nationals, and they may be at risk of arbitrary detention, deportation, and exploitation.

The main solutions to the problem of statelessness are prevention, reduction, and resolution. Prevention involves measures to prevent statelessness from occurring in the first place, such as ensuring that all children are registered at birth and that nationality laws are fair and inclusive. Reduction involves measures to reduce the number of stateless persons, such as providing stateless persons with access to nationality and identity documents. Resolution involves measures to resolve statelessness, such as granting stateless persons citizenship or providing them with a pathway to citizenship.

The UNHCR is the lead UN agency responsible for protecting and assisting stateless persons. It works to prevent statelessness, reduce the number of stateless persons, and resolve statelessness. The UNHCR also provides stateless persons with legal assistance, humanitarian assistance, and advocacy.

States have a responsibility to prevent statelessness, reduce statelessness, and resolve statelessness. This includes ensuring that all children are registered at birth, that nationality laws are fair and inclusive, and that stateless persons have access to nationality and identity documents.

Civil society organizations play an important role in addressing statelessness by raising awareness of the issue, advocating for the rights of stateless persons, and providing assistance to stateless persons. They also work to hold states accountable for their obligations to prevent, reduce, and resolve statelessness.

Civil society organizations face a number of challenges in addressing statelessness, including lack of funding, lack of access to stateless persons, and lack of political will. They may also face discrimination and harassment from governments and other actors.

Best practices for civil society organizations in addressing statelessness include working in partnership with other organizations, building the capacity of stateless persons, and advocating for law and policy reform. They should also document cases of statelessness and raise awareness of the issue.

Emerging trends in statelessness include increasing statelessness due to conflict and natural disasters, increasing statelessness due to discrimination and persecution, and increasing statelessness due to climate change and environmental degradation.

States face a number of challenges in addressing statelessness, including lack of political will, lack of resources, and lack of expertise. They may also face opposition from nationalist and xenophobic groups.