Examples of government companies are:
(i) Coal Mines Authority Ltd.,
(ii) Steel Authority of India Ltd.,
(iii) Indian Telephone Industries,
(iv) Tamil Nadu State Transport Corporation Ltd.,
(v) Tamil Nadu Agro Industries Corporation (Jointly Owned by Central State Govt.),
(vi) Tamil Nadu Small Industries of India Corporation (TANSI),etc.,

Examples of public corporations are:
(i) Reserve Bank of India
(ii) Damodar Valley Corporation
(iii) State Trading Corporation
(iv) Industrial Development Bank of India
(v) Industrial Finance Corporation
(vi) Life Insurance Corporation, etc.,

Examples of departmental undertakings are:
(i) Posts
(ii) Atomic power
(iii) Railways
(iv) Radio and Television
(v) Defence Industries, etc.,

The choice of the particular form of organisation depends upon,
(i) The nature of the industry,
(ii) The circumstances of the country and
(iii) The policy of the government.

The government can establish state enterprises in two ways. They are:
(i) By starting a new unit.
(ii) By taking over an existing industrial or commercial unit owned by private persons.

During the twentieth century, various governments started participating in industrial and commercial activities. Previously, the role of government was limited only to the maintenance of law and order.

The disadvantages of Departmental Undertaking are:
(i) Red-tapism
(ii) Incidence of Additional Taxation
(iii) Lack of Competition.
(iv) Casual Approach to work
(v) Financial Dependence

The advantages of Departmental Undertaking are:
(i) Easy formation
(ii) Direct and Control of Parliament (or) State Legislature
(iii) Secrecy maintained
(iv) Lesser Burden of Tax an Public

The Indian Railways are managed by the Ministry of Railways. Post services are run as a department, under the Ministry of Communication. The Delhi Milk Scheme, All India Radio, Doordarshan are other examples of departmental undertakings.

Arms and ammunition and allied items of defence equipment, defence aircraft and warships,
1. Atomic energy
2. Coal and lignite
3. Mineral oils
4. Minerals specified in the Schedule to the Atomic Energy (Control of Production and Use) Order, 1953
5. Railway transport

i. Departmental undertakings is the form of public enterprises which is most suitable for projects related to National Security
ii. Because Strategic industries like defence and atomic power cannot be better managed other than government departments.
iii. Department undertakings can maintain secrecy in their working.

(i) Private sector enterprises :
i. Sole Proprietors:Designers, Developers, Plumbers and Repairmen
ii. Partnerships: Legal, Accounting, Tax
(ii) Global enterprises:
i. Coca Cola
ii. Colgate Palmolíve
(iii) Public enterprises:
i. Indian Railways
ii. All India Radio

A departmental undertaking is established either as a separate full - fledged ministry or as a major sub-division of a ministry (i.e. department) of the Government.

(i) Departmental undertakings
(ii) Statutory corporations
(iii) Government company
(iv) Board organisation