This act empowers the Central Government and State Governments to detain a person to prevent him/her from acting in any manner prejudicial to the security of India, the relations of India with foreign countries, the maintenance of public order, or the maintenance of supplies and services essential to the community it is necessary so to do.

The act also gives power to the governments to detain a foreigner in a view to regulate his presence or expel from the country.

The Defense of India Act of 1915 was amended at the time of the First World War to enable the state to detain a citizen preventively.

The Rowlatt Committee, approved after the First World War, recommended that the harsh and repressive I provisions of the Defense of India Act be retained permanently on the statute books.

However, this view now stands reversed in Maneka Gandhi's case where the Supreme Court has held that the "procedure established by law" must also be just, fair and reasonable.