Sizwe Banzi is Dead is a critically-acclaimed South African play co-written by Athol Fugard, John Kani and Winston Ntshona. Kani and Ntshona are also the main characters in the play which was first performed in 1972, at the height of the Apartheid system. The writers purposefully chose the topic of the unjust "pass laws" and concentrated on it in an effort to expose its violation of basic human rights. It was a complex system of rules but simplified: black South Africans were required to carry a pass book which gave them permission to work in so-called "white" suburbs. Otherwise, they were required to leave the area within seventy-two hours of having arrived. Domestic workers, office workers and ironically actors - Kani and Ntshona included - could not walk freely on the streets in these areas unless they could prove that they had a legitimate reason to be there which had to be included in the pass book. Failure to provide a pass book (even if it was just lost or forgotten) often resulted in imprisonment. The pass laws were the most despised symbol of the oppressive Apartheid system and the laws were repealed completely in the mid 1980s.
The pass book requirement meant that black South Africans could not move around the country looking for work without putting themselves at risk of arrest. This is the problem for Sizwe who has come to this area of Port Elizabeth to look for work. He has been unsuccessful and so must return to King William's Town before his time there is deemed as unlawful. He has a wife and children to support and there is no work back home so he must take desperate measures to secure a job in this district - even taking the identity of a deceased man; effectively stealing the man, Robert Zwelinzima's identity. The play therefore explores the effects of the pass laws on Sizwe and Styles, the photographer, who only wish for a better future. This also gives the play its universal appeal.
Yes, the themes reveal the South African apartheid system. The primary theme is identitiy in South Africa and the secondary theme is universal identity: how is identity constructed and what is required for identity to be acknowledged and respected, etc. In South Africa non-whites were severely restricted in where they could live, work and travel. Their identity books, called the Book of Life, dectated these restrictions. People caught without them suffered extreme difficulties. Sizwe Bansi is without an identity book and therefore stranded and in grave danger of loosing his freedom because he can't prove his identity and he may be acting outside the bounds of his restrictions. An Answer to a Question in this Sizwe Bansi Is Dead Group may give you more understanding of this.