Why did Biafra face a severe food crisis during the civil war?

During the Nigerian Civil War, the severe food crisis in Biafra was primarily caused by the military encirclement of the secessionist state by federal forces.12

As the conflict progressed, federal troops pressed Biafra’s boundaries inward from the north, west, and south, causing the territory to shrink significantly—eventually to just one-tenth of its original size. By 1968, Biafra had lost its seaports, effectively becoming landlocked and cutting off traditional supply routes. Consequently, the region became entirely dependent on airlifts for food and medicine, which were insufficient to sustain the population. This isolation, combined with the destruction of infrastructure, led to widespread starvation and disease, resulting in an estimated 500,000 to 3,000,000 deaths.123