Here is data from the Cognitive Abilities Test for UK students in 2009/10 via Ambiguous.
Some interesting things to take away here:
(1) The sample is very large. Verbal IQ has the highest correlation with academic performance in most subjects, followed by Quantitative IQ, and then Non-Verbal Reasoning (recognizing patterns and such, I imagine).
(2) Indians do almost as well as Whites, although the structure of their cognitive abilities are a bit different: About 4 points lower than Whites in Verbal, but almost 2 points better in Quantitative. As rec1man said, “The Patels and Sikhs are Upper-Shudra / Vaishya and this is 80% of the diaspora in UK.” So this is highly encouraging for India’s eventual prospects; in indicates that the broad middle can in principle build a reasonably wealthy, middle-class society.
(3) The Pakistanis and Bangladeshis also don’t do too badly – certainly better than I would have expected (I visited a Pakistani school once in the UK and it was horrific).
(4) This might imply we are actually looking at the following average-IQ groups in India: Lower 40% – 93; Middle 40% – 99; Top 20% – 105, for an overall average of 98 (once Flynn Effect is done with them). That’s better than Greece today and certainly good enough to have a developed society. But there’s tons of challenges: Malnutrition, slums, poor education, widespread vegetarianism (both voluntary and involuntary – due to poverty) that have to be sorted out for India to perform to its potential.

One notices a remarkable correlation between this, and the perceived attitudes of local women and their obesity rates.
This may be the article I’ve hesitated longest over publishing. Its subject matter has always hovered as a specter over my writings on 



