Haan kuch states me sub capitals ka system hai with subdivision of powers or having distributed powers like having summer winter legislative sessions in different cities. Don't know if this warrants being called a sub capital of a state
1. Maharashtra - Mumbai and Nagpur. Nagpur holds legislative winter sessions as well as has a special section of Bombai High court - Nagpur bench and reserve bank
2. Andhra Pradesh - Amaravati, Vishakhapatnam and Kurnool are being developed with division of legislative, judiciary and executive powers
3....
more... Jharkhand - 4 sub capitals - Dumka, Medininagar, Chaibasa and Giridih although I do not know about their power distribution. Locals might help us with the info.
4. Himachal Pradesh - Shimla and Dharamshala with the later beingh winter legislative capital.
Uttarakhand also has power distribution with High court in Nainital, although I don't know if its called a sub capital for this. Other people might help to complete this info as I do not have complete info on power distribution of all states of India, would have to research once I am free.