The Territorial Army in India (commonly referred to as TA in India) is an organization of volunteers who receive military training for a few days in a year so that in case of an emergency they can be mobilized for the defence of the country.

It is a second line of defense after the Regular Indian Army

Indian Army

The Indian Army is the land based branch and the largest component of the Indian Armed Forces. With about 1,100,000 soldiers in active service and about 1,150,000 reserve troops, the Indian Army is the world's largest standing volunteer army...

; the Indian Territorial Army is not a profession, occupation or a source of employment. It is only meant for those people who are already in mainstay civilian professions, in fact, gainful employment or self-employment in a civil profession is a pre-requisite for joining the Territorial Army.
The Indian Defence Force

Indian Defence Force

The Indian Defence Force was a part-time defence force established as part of the Indian Army in 1917 in order to release regular troops from garrison duties during the First World War....

, incorporating Europeans and Indians in separate sections, was formed by the British in 1917.