I'm wondering if it would be possible to see the spread of Indianisation along the Eastern African coastline as it did in South East Asia OTL. I see Indianisation as the spread of Indian religious, philosophical and cultural ideas and the emulation by local powers of Indian social and political structures.
The most obvious way would simply to increase the number of Indian traders in Africa, but I have heard that much of the trade between the regions went through Arab middlemen. Removing the middlemen and having more direct trade links may see the spread of Indian ideas. Perhaps some kind of catastrophe affects the pre-Islamic Meccans, removing their influence. This would also remove the later influence of Islam, and perhaps even facilitate the Indianisation of the southern Arabian coastline. This could be the perogative of the Cholas, seeing the spread of Tamil writing scripts and the construction of Hindu temples in East Africa.
There's also the option of turbocharging the Austronesian expansion westward and having Malagasy-like people settle along the East African coastline, who then begin trading with India and apply Indian ideas of caste to their own situation, placing the Austronesian ethnic types above native Africans in their hierachy.
The most obvious way would simply to increase the number of Indian traders in Africa, but I have heard that much of the trade between the regions went through Arab middlemen. Removing the middlemen and having more direct trade links may see the spread of Indian ideas. Perhaps some kind of catastrophe affects the pre-Islamic Meccans, removing their influence. This would also remove the later influence of Islam, and perhaps even facilitate the Indianisation of the southern Arabian coastline. This could be the perogative of the Cholas, seeing the spread of Tamil writing scripts and the construction of Hindu temples in East Africa.
There's also the option of turbocharging the Austronesian expansion westward and having Malagasy-like people settle along the East African coastline, who then begin trading with India and apply Indian ideas of caste to their own situation, placing the Austronesian ethnic types above native Africans in their hierachy.