Movement that takes place outside the regulatory norms of the sending, transit and receiving countries. There is no clear or universally accepted definition of irregular migration. From the perspective of destination countries it is entry, stay or work in a country without the necessary authorization or documents required under immigration regulations. From the perspective of the sending country, the irregularity is for example seen in cases in which a person crosses an international boundary without a valid passport or travel document or does not fulfill the administrative requirements for leaving the country. There is, however, a tendency to restrict the use of the term “illegal migration” to cases of smuggling of migrants and trafficking in persons.