"To make two things absolutely clear. The immediate withdrawal of the NRC is a necessary first step to restore trust and heal the nation," tweeted Guha.
Branding the CAA immoral and against the spirit of the Constitution, Guha admonished that a wise and just government would withdraw it too.
The historian said Prime Minister Narendra Modi must immediately announce that there is going to be no NRC.
"That simple (removing NRC) and single announcement will do more to restore peace and trust than anything else. The country needs a healing touch and from the top," said Guha.
He took an active part in the anti-CAA protests in Bengaluru. On Thursday, the city police detained Guha at the Townhall centre for violating section 144 CrPc, protesting the CAA.
The CAA, passed by Parliament on December 11, is meant to grant citizenship to persecuted Hindus, Sikhs, Parsis and Christ who were minorities in Afghanistan, Bangaldesh and Pakistan, excluding all kinds of persecuted Muslims.
Guha, 61, was later let off, after the police served him lunch, along with several other protesters.
Though many policemen who detained Guha did not know that he was an eminent critic and historian, assistant commissioner of police K. Gouda said the police later got to know his importance and took good care of him.
Earlier, on Monday night, Guha joined hundreds of protesters at the Townhall centre in Bengaluru to protest the CAA.
He said, "We want democracy, we want pluralism."
( With inputs from IANS )