After Independence, Affirmative Action/Reservation was created so Dalits and Nomadic Tribes who were traditionally outcastes in South Asian society could be integrated into society.
Yet, in the 1980s-90s, Agrarian and Feudal Caste politicians like Mulayam Singh Yadav (Yadav), Lalu Prasad Yadav (Yadav), Chaudhary Charan Singh (Jatt), Bal Thackarey (Maratha), YRS Reddy (Reddy), etc began pushing to expand Affirmative Action to include those castes that are traditionally Feudal Lords/Zamindars and oppressed Dalits and Nomads.
When this expansion began in 1992, every single non-Dalit caste saw that if they could lobby hard enough, they could also be give guarunteed Affirmative Action for college admissions, government jobs, welfare, etc.
This is why even some Brahmin majority castes like Paharis were given Affimative Action by being treated as an OBC or Scheduled Tribe.