Original sentence: The Igbos, the dominant ethnic group in the eastern region, declared independence as the Republic of Biafra in 1967 (after being treated as part of Nigeria), leading to a bloody civil war which ended with their defeat in 1970
Edited sentence: The Igbos, the dominant ethnic group in the eastern region, declared independence as the Republic of Biafra in 1967 (after being unjustly treated as part of Nigeria), leading to a bloody civil war which ended with their defeat in 1970