transit visa

Maybe this will help you?

For South Africa Consulate General – Mumbai :
      If you are a national of a non-visa exempt country and are in transit to a neighboring country, you will be required to be in possession of and to produce a valid transit visa upon entering South Africa. The transit visa is applicable for those traveling to neighboring countries i.e. the Kingdom of Lesotho, the Kingdom of Swaziland, Namibia, Zimbabwe, Botswana and Mozambique. Travellers transiting in South Africa en route to any other country do not require transit visas.
      For South African High Commission – Delhi :
      Citizens who are holders of Diplomatic, Official and Service passports of India do not require visas in respect of purposes for which a port of entry visa may be issued or by virtue of being a person contemplated in section 31(3)(b) [accredited in SA] for 90 days and Transit:
      Indian Citizens who are normal passport holders from India do need a port of entry visa to entre South Africa or a Transit visa for transiting in South Africa en route to any other country

Indian Passport holders are exempt from visa fees (Gratis)

Or if that doesn't help you can visit this website for more info:

http://www.sahc.org.au/visas/Transit_Visa.html