It has been conclusively proved that Indus Valley civilisation is about 5000years old as we have discovered lot archeological evidence. Next oldest remains is 2500 years old - that is of Taxila built by Persians. Then we have no archeological evidence of any civilisation till around 300 BC, of some Buddist structures in Nalanda, Sanchi, Ajanta, Ellora, Asokan Pillar/edicts etc. No remains of Pataliputra is available as it was made of timber. In between, we have no archeological evidence of any Hindu or Vedic civilisation. Why it is so? Or were we week in stone/masonry engineering?
Aryans came from central Asia and the only then existing civilization was Dravidian civilization in ancient INDIA, the Budd ism was an offshoot of the Hinduism, the Vedic civilization was not confined to the present geographical foundries of our country . The ancient INDIA was far and wide extended up to present AFGHANISTAN INCLUDING Asia miner ,including territories of present RUSSIAN republics ,hence ,the archeological evidences are related to HINDU or VEDIC civilization are not exclusively confined to present geographical INDIA.