Upvote:1
I will post the estimation made by Angus Maddison, who declares 75 million people. Since he does not include data for that year for Pakistan and Bangladesh, I assume that their population is included in those 75 million.
His dataset (.xls)
Upvote:1
My Go-to source for population numbers is McEvedy and Jones' Atlas of World Population History. It shows the Indian subcontinent with about 79 million people in 1000CE (very close to your first number). There was a more or less steady asymptotic curve up from there, with no noticeable reversals. Here's their graph:
As a sanity check, lets compare with world population in 1000CE. Scott Manning compiled a great graph of all the various number for this. From this it appears that estimates for world population run from about 200 to 500 million, with the general consensus pegging it around 300 million. So, unless that big outlier is right, 200 million for India alone looks quite unlikely.
(You can see my source I used above listed here as "McEvedy and Jones 1978")