“Irregular”, which is sometimes used interchangeably with “undocumented” and “unauthorized”, does not refer to a specific kind of migrant, but to the legal status of a migrant, which can change at any point during their journey or stay in a country. For example, migrants fleeing conflict may be counted as irregular when crossing the border but become regular when applying for asylum. Furthermore, migrants who entered regularly may become irregular when their visa or residence permit expires (IOM, 2022b). The term “illegal” or “illicit” is generally avoided as it may exaggerate an administrative crime, e.g., the overstaying of a visa, creating an unnecessary perception of criminality (IOM, 2018). In 1975, the United Nations General Assembly adopted resolution 3448 (XXX), which requests the UN organs and specialized agencies concerned to utilize in all official documents the term ‘non-documented’ or ‘irregular migrant workers’. Furthermore, as emphasized in a statement from the United Nations High Commissioner for Human Rights in the 12th session of the Human Rights Council (2009), “‘illegal immigrants’ should be avoided and replaced by the internationally accepted definitions of ‘irregular’ or ‘undocumented’ migrants, which more accurately describe the situation” (UNHCR)
While there is no universally accepted definition of irregular migration, IOM (2011) defines it as “movement that takes place outside the regulatory norms of the sending, transit and receiving country”. The United Nations 1994 International Conference on Population and Development defined undocumented or irregular migrants as “persons who do not fulfil the requirements established by the country of destination to enter, stay or exercise an economic activity”. Migrants finds themselves in an irregular situation when a) they have entered the country irregularly, for example with false documents or without crossing an official border point; b) when they reside in a country irregularly, for example without a valid visa or residence permit; c) when they are employed irregularly, for example when they are paid for work even though the conditions of their residence prevent them from taking up employment; or d) they are born in an irregular status/to parents in an irregular status (IOM, 2022b). Irregular migration is not always black and white, for example, while ECOWAS allows people to move freely between the 15 member states for a period of up to 90 days, migrants may still be counted as irregular because they are not in possession of a valid travel document (IOM, 2022b).