In India now social structure is changing gradually, there were days when political supremacy was dominated by forward caste people only and politicians of OBC and sc ,st classes were simply tailenders or just followers.
No one even could think of becoming CM,PM from these classes
Then came jp movement,which produced youth leadership from all classes of society and these leaders brought a revolution post emergency
When Janata party came to power in states, obc leaders like karpoori thakur, ram naresh yadav got chief minister ship in their states.
In eighties when Congress used to rule in most of states, there was a undeclared rule about selection of chief minister e.g. if CM of up is from rajput community, CM of Bihar would be from Brahmin community and vice-versa, same theory was being applied in other states also
There was no consideration of place for obc or dalit community leaders
The jp movement and there on Janata party rule changed the trend upto some extent.
Then came kanshiram’s social justice movement, which changed the political scenerio , completely.
First he created awareness among downtrodden class about their rights and gradually inspired to wisdom of ruling, his movement put big impact on Indian politics, and people started thinking of other classes also.
Mayavati, became an ice breaker in up politics for dalits after becoming Chief minister , which became a milestone for dalit politics, now there are so many OBC and dalit CM in country, which no one could even think of, till eighties.