According to a National Family Health Survey, poor sanitation is a better predictor of child stunting than calorie consumption. However, the study says, that both sanitation and calorie consumption contribute in different ways to health and well-being.

Researchers Dean Spears of the Delhi School of Economics’ Centre for Development Economics; Arabinda Ghosh of the IAS; and Oliver Cumming of the London School of Hygiene and Tropical Medicine used data on stunting from the Hungama survey of 73,000 households in 112 districts conducted by the Naandi Foundation in 2011. To measure sanitation, they looked at levels of open defecation from the 2011 census.

Data from Census 2011 show that close to half of households are forced to defecate in the open. Over three-quarters of the households in Jharkhand, Orissa and Chhattisgarh defecate in the open, while even developed States like Tamil Nadu, Andhra Pradesh, Gujarat and Karnataka have 40-50 per cent open defecation. Just over 10 per cent of India has a toilet with a flush connected to a piped water system.

Spears, Ghosh and Cumming found that open defecation was a strong predictor of child stunting; districts with higher levels of open defecation had higher levels of child stunting, even after controlling for other factors like household expenditure, household size and calorie consumption. A 10 per cent increase in open defecation was associated with a 0.7 percentage point increase in both stunting and severe stunting, they said in a journal article.

Spears showed in an earlier paper that open defecation could explain 54 per cent of the variation in average child height between countries, and 65 per cent when population density was considered. Union Rural Development Minister Jairam Ramesh has acknowledged that the role of sanitation has not in the past been given enough importance.