Why did Pieter Willem Botha resign in 1989?

Pieter Willem Botha resigned as the Prime Minister of South Africa in 1989 primarily due to increasing pressure for political reform amidst growing domestic unrest and international condemnation of apartheid. His government's inability to effectively address the demands for change, along with the declining legitimacy of the apartheid regime, led to his decision to step down. Botha's resignation marked a significant turning point in South Africa's political landscape, paving the way for negotiations to end apartheid.