It is a violation of India's obligations under international law. Specifically, Part 3 of the International Covenant on Civil and Political Rights which India is a signatory of.
No, this is not a violation. It is a crime to enter India illegally, so detention cannot be considered arbitrary.
The single point of controversy is whether the Citizenship Amendment Act can omit a refugee on the basis of religion. The supreme court can issue a ruling on this and end the matter.
