Namibia, then known as South West Africa, had been a German colony until the end of World War I when it came under the administration of South Africa as a League of Nations mandate. However, instead of preparing Namibia for self-rule as intended, South Africa extended its own policy of racial segregation and apartheid to the territory.

As international opposition to apartheid grew, so did the condemnation of South Africa's continued occupation and governance of Namibia. The U.N. Security Council, acting upon its mandate to ensure peace and security, saw the situation in Namibia as a potential flashpoint in the Cold War-era global landscape. The resolution demanding the transfer of power to Namibia's native inhabitants was a manifestation of this concern.

The May 30th, 1975 deadline was significant as it was a culmination of mounting international pressure on South Africa to decolonize Namibia. The fact that it was set by the U.N. Security Council gave it an added weight, as the Council's resolutions are binding on all member states. The world watched closely as the deadline approached, hoping for a peaceful transition to Namibian self-rule.

However, Balthazar Vorster's response ten days before the deadline was a clear indication of South Africa's refusal to relent under international pressure. Vorster's rejection of the UN's demand, specifically his unwillingness to negotiate with the South West African People's Organization (SWAPO), was emblematic of South Africa's broader stance on apartheid and white minority rule. SWAPO, being the principal nationalist group pushing for Namibia's independence, represented the aspirations of a significant portion of the Namibian populace.

Vorster's intransigence further isolated South Africa in the international arena. The subsequent years witnessed escalating guerrilla warfare in Namibia, with SWAPO engaging in armed struggle against South African forces. The international community, led by the U.N., continued to exert pressure on South Africa through various means, including sanctions, to bring an end to its occupation of Namibia.

In conclusion, the U.N. Security Council's demand and the subsequent rejection by Balthazar Vorster was not just an isolated diplomatic incident but a significant episode in the long and arduous journey towards Namibian independence. It highlighted the global community's commitment to ending colonial rule and the defiance of an apartheid regime determined to maintain its hold on a territory it considered its own.