Section 79
Suits by or against Government
Part IV: Suits in particular cases
In a suit by or against the Government, the authority to be named as plaintiff or defendant, as the case may be, shall be—
(a) in the case of a suit by or against the Central Government, [the Union of India], and
(b) in the case of a suit by or against a State Government, the State.
The Code of Civil Procedure, 1908 (Act No. 5 of 1908). From the updated text on India Code, with later amendments. Being checked against the official copy; amendment notes are not shown yet.