Being rich insulates rich Indians from most things... but not from being short.

I wrote earlier this week about new data that showed that districts with the highest levels of open defecation had the highest proportion of stunted children. The point at which explanations for the causes of India’s malnutrition some times break down for me is at the top 5%.

The top 5%, of which you and I are all a part, leads a reasonably good life. So if poor sanitation is linked with India’s low heights, why isn’t someone like me, whose family has been lucky to for three generations have had access to toilets, as tall as a European woman? (I’m not, sadly.) The answer has a lot to do with… well, the nature of poo.

Open defecation, says Dean Spears, an economist who has done a series of studies on the impact of open defecation on child stunting, is a classic “public bad”. Think of it as the opposite of a public good, which has positive spillover effects beyond its immediate purpose. A ‘public bad’ on the other hand has negative effects far beyond its immediate implications. The presence of fecal matter in the physical environment can cause diarrhoea which rids the body of nutrients, and can also make it systematically harder for the body to absorb nutrition.

The neighbourhood I live in in New Delhi is relatively well off, but there is a fairly large slum just 500 metres down the road. Having been there to meet people, I know that there are open drains which flood badly in the rains. It isn’t hard to imagine that fecal matter enters the water and food of the slum’s residents.

My experience is borne out by Spears’ numbers: he identified an “elite top 2.5 percent of the Indian population: children who live in urban homes with flush toilets that they do not share with other households; whose mothers are literate and have been to secondary school; and whose families have electricity, a radio, a refrigerator, and a motorcycle or car.” The children in this elite sub-set too are shorter than expected, “because 7 percent of the households living near even these rich children defecate in the open”, he found.

If not for moral reasons (which I despite being a numbers person tend to favour), there are good scientific and selfish reasons for all of us – and not just those without toilets – to press for an end to open defecation.

(For a good illustration of the geographical spread of toilets, and hence also lack thereof, see this fantastic, painstaking map from the Data Stories blog.)