India has ratified Hague Convention #33 on intercountry adoption. South Africa has also ratified. As a result, all international adoptions from India must be conducted under the rules of the Convention. Be aware that private adoptions from India will not be allowed, even by people of Indian origin.
Your first step will have to be identifying an adoption agency in South Africa that is accredited by the South African government to conduct Hague adoptions, and that is also approved by India's Central Adoption Resource Agency (CARA). Based on my quick look at the CARA website at
Central Adoption Resource Agency, there is only one South African agency that meets these criteria. The contact information for that agency is on the CARA website.
That agency will lead you through the steps of applying to adopt from India, and will also help you to comply with South Africa's immigration requirements for internationally adopted children. Remember that all international adoptions have two components -- the actual adoption, and the immigration of the child to the new parents' home country.
Sharon