No support for the entry of ‘Aryan’ populations [in India] is found in physical anthropological data (Petraglia & Allchin 2007) - Bridget Allchin

Such "ritual hearths" are reported from the beginning of the Harappan period itself. It has been suggested that they may have been fire altars , evidence of domestic, popular and civic fire-cults of the Indo-Iranians, which are de- scribed in detail in the later Vedic literature. It may then be an indication of culture contact between an early group of Indo-Aryans and the population of the still-flourishing Indus civilization.

From early historical times forward we know that horses have been regularly imported to South Asia. We also know the Indus had a long tradition of trade with centres to the west and north. Would it be surprising therefore if horses were occasionally acquired through trade, ultimately reaching the Indus world by land or sea? This would account for the occurrence of a small number of their bones in various contexts without the need to assume their presence must necessarily be associated with profound cultural change.

Their [the Aryans] presence should therefore be in evidence archaeologically… But as yet it is scarcely attested in the archaeological record presumably because their material culture and lifestyle were already indistinguishable from those of the existing population.