Why the classifications of Indian populations, based on somatometric and somatoscopic characteristics failed to develop a common understanding of the population diversity? (Answer in 250 words)

- Why the classifications of Indian populations, based on somatometric and somatoscopic characteristics failed to develop a common understanding of the population diversity? (Answer in 250 words)
Introduction
The racial classifications of India did not fail for want of data. They failed because the characters chosen could not carry the classification, and because the idea of a racial type was itself untenable.

Body
1. What they attempted: Risley, Guha, von Eickstedt, Majumdar and Sarkar each tried to resolve the Indian population into a few racial elements using measured characters — stature, cephalic index, nasal index, facial index — and graded observations of skin colour, hair form, eye colour and the eye fold. Risley's seven types and Guha's six from the 1931 Census survey are the standard schemes.
2. The methodological defects: landmarks, instruments and grading scales were not standardised, so one worker's series could not be compared with another's. Somatoscopic traits were judged by eye, under varying light, and disagreed between observers. Samples were small, overwhelmingly male, opportunistically drawn and taken by caste or tribe, with caste simply assumed to be a breeding population. Results were reported as means without variance or significance tests. Worst, the characters are plastic — Boas had already shown the cephalic index shifting within one generation of migration.
3. The conceptual defects: the schemes were typological, treating a series mean as a type and every individual as a deviation from it. But the traits vary continuously and clinally, and each varies independently, so a classification by nasal index cuts across one by head form. Millennia of admixture leave no discrete units to find.
4. What later evidence showed: blood groups and then DNA replaced the indices.

Conclusion
Indian genomics now describes the population as varying mixtures of a small number of ancient ancestries, structured by endogamy and founder effects rather than by race. The old schemes survive only as a chapter in the history of the discipline.