How accurate is the Indo-Aryan migration theory? What are your views on the new archaeological evidences found in North India that completely debunk this theory?
How accurate is the Indo-Aryan migration theory?
It is well-supported by linguistic evidence, genetic evidence, archaeology showing the spread of technologies with it, and cultural evidence (e.g., similarities in religions).
Further, the Indo-Aryan migration theory doesn't stand alone - it's the southern direction of the larger Indo-European expansion, which also went east and west.
There is nothing incredible about the idea of a movement of peoples, languages, ideas, and technologies as required by the Indo-Aryan migration theory. There were earlier and later movements as well. For example, an expansion of early farming peoples across Europe from the SE with the main technology they carried being farming, a movement of Germanic peoples from Germany through Spain and into North Africa, the Arab conquests, the Turkic expansion, and more recently the spread of European peoples to the Americas and Oceania.
What are your views on the new archaeological evidences found in North India that completely debunk this theory?
If you mean the recent archaeo-DNA studies showing that the Harappan peoples were not Indo-Aryan migrants, this debunks nothing, since it has long been well-known that the old Indus valley civilisations developed long before the Indo-European expansion. Indeed, it had been suggested that the Harappan civilisation fell due to Indo-Aryan invasion (but the current consensus is that the Indo-Aryan arrival was later (and was perhaps enabled by the fall of those civilisation)).
Why would such DNA studies be presented as debunking the Indo-Aryan migration? The Indo-Aryan migration theory is deeply offensive to many nationalists, especially Hindu nationalists since it would mean that Hinduism isn't an age-old indigenous Indian religion, but a "recent" arrival less than 4,000 years ago. These studies provide convenient (if dishonest) propaganda, even if they have nothing to do with the Indo-Aryan migration theory. This kind of political use can arise from within the group of researchers; it isn't always outside groups trying to exploit it.
The politicisation of the issue can be seen in this news article:
wherein we can see that at least some of those who criticise such propaganda prefer to remain anonymous:
"Rakhigarhi doesn’t really apply to the Aryan period. It’s prior to that," said an eminent historian not linked to the study, who was not willing to be quoted.
One extreme nationalist "theory" to explain linguistic and cultural similarities proposes a south-to-north movement. That is, the Aryan resembles the Indo because it came out of India. This fails badly on the genetic evidence, and this Harappan evidence basically debunks a south-to-north movement and supports a north-to-south movement. If "Aryan invasion genes" are not to be found in the Harappan civilisation, and they are found later (which they are), then they came from somewhere. That somewhere is from the north.
Thus, we can see here an interesting case: evidence that supports an Indo-Aryan movement of peoples is claimed instead to debunk it. The perils of highly politicised science and history!
If you mean other recent studies/discoveries, can you give more information?