Question: Bancoult v McNamara challenged the removal of Chagosians from what atoll just south of the equator in the central Indian Ocean, which is the largest of 60 small islands comprising the Chagos Archipelago?

Context paragraphs:
North Brother (Chagos Bank): North Brother, also known as Île du Nord, is a round 6 ha coral island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory.  It is one of the three islands in the Three Brothers group on the western side of the atoll, and forms part of the Chagos Archipelago strict nature reserve.  It has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for 20,000 seabirds, notably Audubon's shearwaters of which 420 pairs were recorded in a 2004 survey.

List of Lepidoptera of the Chagos Archipelago: Lepidoptera of the Chagos Archipelago consist of both the butterflies and moths recorded from the islands of the Chagos Archipelago, a group of seven atolls comprising more than 60 tropical islands in the Indian Ocean.  The archipelago consists of five emergent atolls, Diego Garcia, Egmont, the Great Chagos Bank, Peros Banhos and Salomon.  There are also several submerged atolls and vast banks and shoals.  The whole territory covers 54,400 km of the Indian Ocean, of which the archipelago covers about 37,500 km.  The Chagos Archipelago has been British territory since 1814 and was made a dependency of the United Kingdom in 1965.

1983 Chagos Archipelago earthquake: The 1983 Chagos Archipelago earthquake occurred on November 30 at 17:46 UTC in the region of the Chagos Archipelago, British Indian Ocean Territory.  This earthquake had a magnitude of M 7.7.  This earthquake occurred in the Indian Plate near the Central Indian Ridge.  The Central Indian Ridge is unusually active in near-ridge earthquakes.  The intense seismic activity in this region may indicate an early stage of converging plate boundary, which is responsible for the N-S extension near Chagos.  There was a 40 cm tsunami reported in Victoria, Seychelles.

Diego Garcia: Diego Garcia is an atoll just south of the equator in the central Indian Ocean, and the largest of 60 small islands comprising the Chagos Archipelago.  It was settled by the French in the 1790s and was transferred to British rule after the Napoleonic Wars.  It was one of the "Dependencies" of the British Colony of Mauritius until it was detached for inclusion in the newly created British Indian Ocean Territory (BIOT) in 1965.  Between 1968 and 1973, the population was forcibly removed by the United Kingdom and the United States (in order to establish an American base) through intimidation of locals and denying the return of any who left the island.  Many were deported to Mauritius and Seychelles, following which the United States built a large naval and military base on Diego Garcia, which has been in continuous operation ever since.  s of 2015 , Diego Garcia is the only inhabited island of the BIOT; the population is composed of military personnel and supporting contractors.

Chagos Marine Protected Area: The Chagos Marine Protected Area, located in the central Indian Ocean in the British Indian Ocean Territory of the United Kingdom, was established as one of the world's largest marine protected areas, and one of the largest protected areas of any type (land or sea) on Earth.  It was established by the British government on 1 April 2010 as a massive, contiguous, no-take marine reserve, it encompasses 640,000 km2 of ocean waters, including roughly 70 small islands and seven atolls of the Chagos Archipelago.

Sea Cow Island: Sea Cow Island, also known as Île Vache Marine, is a round 18 ha island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory.  It was named after Dugongs that were once abundant in the area although they became regionally extinct.  It is the smaller of the two islands in the Eagle Islands group on the western side of the atoll and forms part of the Chagos Archipelago strict nature reserve.  It has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for brown noddies, of which 11,500 pairs were recorded in a 2004 survey.

Bancoult v McNamara: Bancoult v McNamara was a 2006 legal case in which Olivier Bancoult challenged the removal of Chagosians from Diego Garcia when the United States of America built a military base in British Indian Ocean Territory.  The court ruled that the case raised nonjusticiable political questions and dismissed the case.

South Brother (Chagos Bank): South Brother, also known as Île du Sud, is a 23 ha coral island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory.  It is one of the three islands in the Three Brothers group on the western side of the atoll, and forms part of the Chagos Archipelago strict nature reserve.  It has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for seabirds, including brown noddies (with 6100 breeding pairs recorded in a 2004 survey) and lesser noddies (7300 pairs).

List of islands in Chagos Archipelago: The following is a list of islands in Chagos Archipelago.  The Chagos Archipelago is a group of seven atolls comprising more than 60 individual tropical islands in the Indian Ocean; situated some 500 km due south of the Maldives archipelago.  The archipelago is a British Indian Ocean Territory.

Middle Brother (Chagos Bank): Middle Brother, also known as Île du Milieu, is an 8 ha coral island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory.  It is one of the three islands in the Three Brothers group on the western side of the atoll, and forms part of the Chagos Archipelago strict nature reserve.  It has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for seabirds, notably sooty terns of which 12,500 pairs were recorded in a 2004 survey.

Supporting paragraphs: Bancoult v McNamara Diego Garcia
Answer: Diego Garcia