What are the different kinds of organisations that come under the public sector?

The forms of organisations that come under public sector are
(i) Departmental Undertaking These enterprises are established as departments of the ministry and are considered as part or an extension of the ministry itself. These undertakings may be under the Central or the State Government.
For examples, Railways and Post and Telegraph Department.
(ii) Statutory Corporation Statutory corporations are public enterprises brought into existence hy a Special Act of the Parliament, which defines its powers and functions. It is a financially independent corporate body created by the legislature and has a clear control over a specified area or a particular type of commercial activity.
(iii) Government Company According to the Indian Companies Act, 1956, a government . company means any company in which at least 51 % of the paid up capital is held by the Central Government or by any State Government or partly by Central Government and partly by one or more State Governments. These are established purely for business purposes.