Explanation:

- The Indian national census recognises several societal groups to ensure accurate demographic data collection.

- Tribal groups: These are indigenous communities often referred to as Scheduled Tribes. They are recognised and often have special provisions for their upliftment.

- Ethnic groups: While India is ethnically diverse, the census primarily categorises people based on language, religion, and castes rather than distinct ethnic groups.

- Religious groups: The census records religion, which includes major religions like Hinduism, Islam, Christianity, etc.

- Scheduled caste groups: These are explicitly recognised by the government to address historical disadvantages faced by certain castes.

The national census does not specifically recognise ethnic groups.