An Asylum seeker or refugee is an individual who was been displaced from his or her home region due to war and violence; famine or out of fear of persecution, and seeks to live in a foreign nation. The Unified Earth Government reacted negatively to colonial asylum seekers during the latter years of the Human-Covenant War, interning them in camps when identified as "illegal aliens", along with survivors of glassed colonies such as Coral when their entry visas were refused.
In the period immediately after the Human-Covenant War, refugees from the former Covenant member and client races sought asylum on Earth, leading to the South American city of Rio de Janeiro becoming a hotspot for migration (whether it has been outfitted for such an event, or is simply a popular destination is uncertain). Not all asylum seekers migrate to a host country for legitimate means; at the time of the Didact's attack on Earth, elements of Spartan were tasked with stopping a Sangheili terrorist from detonating a HAVOK tactical nuclear weapon.[1]