I didn't know about it but I've recently seen this syllables when I was looking up Kodaly.

I think Sa Re Ga Ma Pa Dha Ni Sa is not corresponding to the C D E F G but to the moveale Do Re Mi.

yes it is:

These seven swaras are shortened to Sa, Ri (Carnatic) or Re (Hindustani), Ga, Ma, Pa, Dha, and Ni. Collectively these notes are known as the sargam (the word is an acronym of the consonants of the first four swaras).

Sargam is the Indian equivalent to solfege, a technique for the teaching of sight-singin. The tone Sa is, as in Western moveable-Do solfège, the tonic of a piece or scale.

https://en.m.wikipedia.org/wiki/Svara

I didn't know about it but I've recently seen this syllables when I was looking up Kodaly.

I think Sa Re Ga Ma Pa Dha Ni Sa is not corresponding to the C D E F G but to the moveale Do Re Mi.

yes it is:

These seven swaras are shortened to Sa, Ri (Carnatic) or Re (Hindustani), Ga, Ma, Pa, Dha, and Ni. Collectively these notes are known as the sargam (the word is an acronym of the consonants of the first four swaras).

Sargam is the Indian equivalent to solfege, a technique for the teaching of sight-singin. The tone Sa is, as in Western moveable-Do solfège, the tonic of a piece or scale.

(may be you'll have to look up "movable do" or "moveable do re mi" here in this SE, you'll find a lot explanations.)

https://en.m.wikipedia.org/wiki/Svara