Johannesburg is the capital of Gauteng, which is the South African province with the biggest population comprising approximately the 24 percent of the overall population. As of 2016 Johannesburg had an estimated population of 4.4 million, and according to the census, the city has grown at an extremely high rate: an average of 4.1 percent between 1996 and 2001 and by 3.2 percent between 2001 and 2011. Although this urbanisation boom is projected to slow down, Johannesburg is expected to reach 7 million inhabitants by 2040.

Durban is located on the east coast of KwaZulu-Natal (KZN) Province in South Africa and eThekwini Municipality is the local government responsible for management and service provision across the eThekwini Municipal Area. Durban is the third most populous city in South Africa and the largest city in the South African province of KwaZulu-Natal. Durban forms part of the eThekwini Metropolitan Municipality and has a population of about 3.9 million.