@Pratap If you read this: Early India: From the origins to the AD 1300, it says:
1) Indo-European and
Indo-Aryan are language labels, but in the nineteenth century these were also incorrectly used as racial labels and this confusion persists. The correct usage should be "Indo-European-speaking people" and `Indo-Aryan-Speaking-people', but the shortened labels, Indo-European and Indo-Aryan are commonly used.
Language is a cultural label and should not be confused with race, which although also a social construct, claims that it has to do with biological descent.
2) Some migrated to Anatolia, others to Iran, and some among the latter it is thought migrated to India.
In the texts composed by them, such as Avesta in Iran and the Rig-Veda in India, they refer to themselves as airiia and arya, hence the European term, Aryan.
3) There are clearly many sources of information on the beginings of Indian history. Archeological evidence is chronologically more precise, but cannot be used to identify any culture as 'Aryan' since archeology, in the absence of a script cannot supply information on a language. Unfortunately, the Harappan script remains undeciphered. The theory of an Aryan invasion no longer has credence.
Romila Thapar is a well-known historian. As per her, there was no Aryan Invasion.
Aryan is a language label. Aryans composed Rig Veda.