Its pretty diabolical.You must be very naive. NRC and CAA are tied at the hip. They are designed to work like this:
First all Indians will be required to prove their citizenship for NRC. If Hindus, Jains, Sikhs or Parsis fail the citizenship test they will be covered under CAA and will automatically get citizenship, however if Muslims fail the test they become become illegal. On a stand-alone basis, CAA seems pretty harmless but combined with NRC it is nothing but a first step towards cleansing India of Muslims. It is a sword hanging on the Muslims, accept the domination of Hindus, become second class citizens, loose your separate identity, become Hindus or leave the country.