How did the Nigerian Civil War end in 1970?

The Nigerian Civil War concluded in January 1970 following the collapse of the secessionist state of Biafra.

By late 1969, Biafra was severely weakened, controlling only a small fraction of its original territory and suffering from critical shortages of food and ammunition. The final collapse began on December 24, 1969, when federal troops launched a massive offensive. As the military situation became untenable, the Biafran leader, Odumegwu Ojukwu, fled to Côte d’Ivoire on January 11, 1970.123

Four days later, on January 15, 1970, a Biafran deputation formally surrendered to the federal government in Lagos, effectively ending the war and the existence of Biafra as an independent state. Following the surrender, General Yakubu Gowon pursued a policy of reconciliation, integrating the former Biafran states back into Nigeria without assigning blame for the conflict.321