Ābhīra (Abhira) is an ancient tribe dwelling in the basin of the river Saraśvatī (Saraswati). In Mahābhārata(Mahabharata) and Purāṇa (Purana), we find that ‘Abhīra’ is mentioned along with the Śūdra (Sudra) people —
śūdrābhīragaṇāścaiva ye cāśritya sarasvatīm.
In the army of Kārtavīryārjuna (Kartaviryarjuna), the Ābhīra people were included along with other non-Aryan tribes.During the battle between Paraśurāma (Parasurama) and Kārtavīryarjuna, many Ābhīra warriors got killed. After the death of Kārtavīryarjuna, the surviving Ābhīra people fled in order to save their lives, and thus they failed to perform the last rites of their dead co-fighters, according to the behaviourial code of the Kṣatriya. It is for this sin, the Ābhira were disgraced and came to be treated as Śūdra (Sudra).
In one śloka (sloka; verse) of Śalyaparva (Salyaparva), it is said that the sacred river Sarasvatī, getting angry with the Śūdra and the Ābhīra people, disappeared into the ground.