It's simple
NRC is planned across India
NRC in Assam however was a failure from a hindutva point of view because it sweeped up shit loads of Hindus
So how do you initiate NRC to specifically target Muslims but not catch millions of Hindus
Answer = CAB
You make a biased law giving automatic citizenship to Hindus and not Muslims
So when you do NRC you can have two people and Hindu gets protection under CAB but Muslim loses voting rights, property rights etc
Indian Muslims have just had enough of being targeted