Monthly Archives: August 2015

Muslim Population Growth: Sex Ratio & Rural Populations

The common refrain of many when Census data showed high Muslim growth rates was: look at Kerala. Let’s look.

Two factors that were reported by the Census data and pointed to as factors that could, at least in part, explain the higher growth rates of Muslims were: sex ratio and percentage of rural population. It’s a reasonable hypothesis. After all, fewer women mean fewer women who can bear children and vice-versa. Similarly, a greater percentage of rural population means more people with lower socio-economic status pointing to higher fertility rates. But is that hypothesis, while well founded in literature[1], hold up within the data set[2] released?

The first thing one does when told one variable may be predicting another is to simply plot the data, before any analysis. A plot of rural population in various states as X and Muslim growth rates in population as Y looks thus.



A similar plot against sex ratio is,


There really is nothing discernible to the naked eye from these scatter plots. If anything, it appears more women correlates to lower growth rates. Not higher.

The next thing we’d do is simple linear regression. There seems to be no linear relationship between rural population and growth rates for Muslims. There isn’t an exponential relation either. But the data for sex ratio among Muslims is a tiny bit more interesting. At least within this flawed model which predicts nothing, if at all there is a wager it’s that more women seems to point to lower rates of growth. 

It’s useful in such cases to just see the two variables interact on a response surface. For this purpose, let’s model this as a Gaussian Process[3].



As we’d expected, the response surface doesn’t move much except for the places X2 acts up. X1 is rural population and X2 is female population as a percentage. The basic point of the data that Muslims have higher growth rate is captured well, though. To understand that even better, let’s look at how the corresponding response surface for Hindus looks,

HinduGPAgain, there is no evidence for rural populations outpacing their urban peers, much. But female population seems to suggest a concentration in the middle and a plunge when the ratio of women increases. The scatter plot of Hindu women and their population growth is in this direction as well,


Of course we know from living in the real world that more women are not resulting in lower population growth. The reason is likely to be the reverse: socially advanced states have better sex ratios and low fertility rates, resulting in low growth.

With the data that’s been released by Census, there isn’t a conclusive model for anyone to conclude reasons within this set. There isn’t even a bad model. But we at least know the hypothesis that lower IMR and hence better sex ratio is a contributing factor to high Muslim growth rates has no evidence. Rural population ratios don’t seem to matter, either.

[1] – Demography as a Science is far too advanced for lay people to just make stray observations. When searching for the model Demographers use to estimate human population, I found this thesis; it’s quite useful as background reading material. Hopefully, I’ll understand the models better in the near future.

[2] – Data used here is the from the same source as the previous post: Census of India.

[3] – Please do not take this to mean anything more than an illustration of the variable’s effects. The GP here is not a real model given how limited the data is. And don’t blame me if you get a failing grade for doing this in class.

[4] The Model details, if you are interested in wrong models that is, of the two GPs.

Muslim Population Growth

Muslims, as a group, have a higher population growth compared to Hindus in India. The headlines told you that already. A state level analysis is, however, what one’d like to look at this instance. Cherry picking, for instance, Kerala’s lower growth in Muslim population compared to Bihar/Uttar Pradesh doesn’t do justice to the data.

A plot of Hindu and Muslim population growth rate — that is the annual population growth rate and not the absolute growth rate — against the total annual population growth rate for each state shows up thus.


Many of us would like to think this is explained by low levels of education and poverty among Muslims. But that too isn’t borne out by the data. The population of Scheduled Castes in each state has been growing at a much lower rate compared to Muslims[1]. Both groups are disadvantaged and thus higher fertility owing to those factors doesn’t explain the premium that Muslim population growth rate seems to have.

The Muslim growth rate across states seems to be less explained by that particular state’s local factors, as suggested by a lower R squared value. Whereas, the Hindu growth rate has a high R squared and seems to have settled into a pattern. This is somewhat expected since the total population in a Hindu dominated society will be explained by Hindu population growth. But the difference in value is there for us see. The data point that explains this best and is perhaps the most surprising part is: the annual population growth rate of Muslims in Tamil Nadu/Maharashtra is higher than that of Hindus in Uttar Pradesh/Madhya Pradesh.

The other factor that explains the Muslim premium is: the far end of high population growth is where it converges with Hindu rates. But that’s after exponentiation in the Hindu rates; except Bihar most states have settled into lower rates of growth.

The Hindu right may exploit this for conspiracy theories. But that’s no reason for the rest of us to pretend socio-economic factors that result in lower fertility have an equal effect on population growth rates of Muslims and Hindus. They don’t seem to.

[1] – The data of Scheduled Caste population growth is so uneven among states that something seems wrong with it. That’s why I haven’t plotted it. Perhaps migration explains that. But I wasn’t sure.

[2] – All data from Census. If you have trouble getting 2001 data for you analysis, please leave a comment.

[3] – This does not change the relationship between fertility and female education levels as argued here. But as every example problem in basic arithmetic class taught us, population grows exponentially.

Politics of Prohibition

The relationship that Asian societies have with alcohol is very different from that of the Alcoholics Anonymous prism through it’s largely viewed in contemporary popular culture. The special place rice and sake enjoy in Japanese society, for instance, is something that’s far removed from the puritan roots that this prism deploys. The wonderfully chronicled exploration Japan, Alcoholism, and Masculinity: Suffering Sobriety in Tokyo makes this case forcefully.

Paul Christensen details how drinking as a social ritual defines masculinity and therefore is considered essential for men in Japan. To the extent that staying sober for recovering alcoholics is a near impossible task. One is tempted to hypothesize that such social custom prevails in all agrarian societies that grow labor intensive crops like rice. Viewed from that perspective, the modern cry for prohibition in Tamil Nadu not only seems like the hollow cry of a politician but also one that ignores civilizational ethos.

The recent opposition noise on prohibition, however, can be understood in simple political calculus of conventional wisdom. All political parties, rightly or wrongly, believe that prohibition is an issue that wins at least some women and some votes. This was true of 1920s America and it’s true for 1970s Tamil Nadu. It’s also a simple fact of politics in Tamil Nadu that the AIADMK enjoys a double digit lead over DMK among women. This has been true for a long time. The appeal of Jayalalitha as a lonely woman battling the men of an ugly system being the reason why many women vote for her despite all her flaws has far too many anecdotes and no real study to back it up. But the corollary that the DMK is essentially a party of urban working class men is well entrenched even among the party’s own cadre.

The numerical supremacy of AIADMK as the largest party in Tamil Nadu is supported by how its losses in terms of actual votes when it’s defeated is never as bad as that of the DMK. When all other things are equal and all parties contest independently, the AIADMK is most likely to win. An opposition party in such a scenario will look to erode the advantage among women. That’s simple politics. But the other question is: why now?

The answers may be varied. Perhaps the DMK hired new political consultants who focus group tested and found this to have increased resonance. Perhaps the DMK was forced into it because smaller parties were otherwise using this issue to usurp opposition space. But whatever the case, that M Karunanidhi, MK Stalin and Durai Murugan actually stood/sat on a stage and said prohibition was their struggle does raise a chuckle. One that is far more worthy of thought than the laughter a similar invocation by Vijayakanth evokes. It was the DMK, when MGR revoked prohibition, that made the only argument remotely in favor of prohibition in poor societies: the excise duty on alcohol shifts the burden of taxation as a percentage of revenue that the state earns towards the poor.

Somewhere, one thinks, M Karunanidhi would have silently read and translated Paul Christensen into Tamil.

Desertification of Tamil Nadu: Private Wells & Paddy

To understand the scale of Tamil Nadu’s water woes, let’s understand what the demand is and how much water there is to divvy up. The demand estimate by the various sectors are,



This 1,894 TMC is well beyond total assessed water resources in the state which is 1,587 TMC. In other words, the demand is 19.3% over and above known supply. So even if there’s good/normal rainfall in Tamil Nadu, the demand exceeds supply. Partly because we discharge fresh water into the sea in some cases and because we haven’t invested enough in processes to recharge aquifers. But even if all of that is done, it’s unlikely this deficit will vanish.

With agriculture/irrigation taking up 93% of the demand, that becomes the only segment that demands our attention. Sure the City of Chennai and its bourgeoisie waste a lot of water or appear to when measured on per capita consumption of domestic water compared to their rural counterparts. But that’s inconsequential in the overall scheme of things. Water scarcity in Chennai does not cause desertification. While Tamil Nadu’s unsustainable sectoral allocation will.

To understand where this 93% water largely gets used, let’s look at Tamil Nadu’s land use pattern. Tamil Nadu’s land area that is sown is 38.3% of its total surface area. That to those of us who aren’t familiar with the data, sounds like a staggeringly high number. Let’s understand where these farmlands are, and to what extent.


With the exception of Chennai, every district has a significant portion of its land sown. For some of the districts, like those in the Cauvery Delta, it’s more than 50% of their total surface area. And with multiple schemes that have been announced, there has even been a tiny growth in this share. As a point of comparison, one world’s largest and most productive agricultural state, California, has 27% of its surface area as cropland. And that state is now contemplating reducing that to conserve water.

The state does seem to have too much of its land under cultivation; it is a lower riparian state of a contentious water treaty and has an annual rainfall far less than states to the west of Western Ghats. An important question then becomes, what are the kind of crops that are grown in Tamil Nadu? What’s their water usage and how are they distributed.



Paddy crops occupy 32.3% of the total area sown in Tamil Nadu!

A state that’s water deficient has about a 38.3% of its overall land cropped in some way and 32.3% of that as one of the most hydrophilic crops known to man: Paddy. That’s 12.3% of the total surface area of Tamil Nadu! In absolute terms, over 1.9 Million Hectares. Of just Rice. That needs standing water.

Now, let’s look at where Rice is grown in the various parts of Tamil Nadu so we can correlate with our earlier findings on ground water level drops.


As one’d expect the Cauvery Delta districts have paddy in over 60% of their sown land. There are other districts which also reach over 60% for paddy. But, as the previous chart showed us, the Delta districts also have the maximum total area under cultivation. For instance, Kancheepuram and Sivagangai – two districts that aren’t in the Delta – have about 20 to 30% of their overall land area sown for any crop. And 70% of that, while still above state wide average, is about 14% – 21% of their total land area.

The Delta districts of Thanjavur, Thiruvarur and Nagapattinam have 60 to 70% of their total land area sown – for all crops. And of this, again have 60-70% under paddy. That means about 40-50% of their total surface area is occupied by water guzzling paddy crops!

The reason paddy or any other hydrophilic crop is an issue in Tamil Nadu is: the state maxed out on surface water irrigation sometime in the 1960s. That capacity has remained stagnant; as a result, the share of private tube and bore wells have dramatically increased. The current share of such wells forms well over 50% of irrigation sources.



Is it the case that these open/tube/bore well are primarily used for paddy? Let’s take a look at where the private wells are and how the various types of wells are distributed.



Thanjavur stands out as a district with a large number of private wells and a significant number of them being bore wells that suck water out at rates that are difficult to replenish.  While Namakkal and Erode basically have come to a situation where marginal farmers who cannot afford a bore well can’t farm.

Coastal districts of northern Tamil Nadu, historically a region irrigated by tanks, now have most wells among regions. The risk there, one’d imagine, is water turning saline more than a drop in ground water levels.

The current classification of ground water by blocks by Government of Tamil Nadu is already alarming.


The shift from rice to another crop is something that is inevitable in the short term. And in the long term, this state cannot afford to have 38% of its area cropped. The proposed amendments that were recently withdrawn – one where farmland can be acquired without consent – may be a necessity soon in Tamil Nadu for a very different reason. One where the government tells the farmer: the society cannot afford the luxury of you farming.

Data Sources:

1.  Season and Crop Report, Tamil Nadu for 2011-12. A scanned version is available here.

2.  Tamil Nadu Water Supply and Drainage Board gave the demand estimate.

On reacting and not being reactionary

In the past few weeks, the Twitter handle associated with this blog has been deactivated. It’s been a remarkably clutter free environment in terms of thought. A need to react has a point of no purchase that Plato, surely, did not recognize. And it’s easy to rationalize that this relative silence is an objectively better place if one’s purpose is expanding one’s own thought; to the extent one’s own ability limits it. Of course that’s not true in all cases and someone far more erudite has already written an essay that touches on the topic while extolling Max Beerbohm.

The polarization of opinion on all forms of media, and particularly in shorter forms, often surprises us by its effect on ourselves. After all, we think, we are beyond the petty tribalism of everyone else. But the constancy and the immediacy of the medium forces one to seek out how intolerable the intolerant are. That seems to be the natural equilibrium of mass participation.

Consider the recent remark that an AIADMK MP made: he’d cut off tongues that spoke ill of J Jayalalitha’s health. No reasonable person in Tamil Nadu takes that seriously. The people of the state engage with Dravidian politics with the same common sense that Antonio Gramsci credits the subaltern of; the set of cultural pre-suppositions which define that common sense extend to the semantics of Dravidian politics. But someone who’s not from the state or does not form part of the in-group that Gramsci defines will find it shocking. No wonder Delhi found it that and picked it up.

If one is able to understand a Tamil politician thus, does the same argument apply for Hindutva rabble rousers of North India? To think of it, it does sound unlikely that a man who writes atrociously bad poetry will go around cutting hands of people. Narendra Modi, for all the image makeover he’s received, is still a provincial politician with particular cultural pre-suppositions that act as his common sense. Does a person in Madras then give the incumbent Prime Minister an ‘I don’t know’ grade for his earlier speeches in Gujarat that sound like ugly Islamophobia? Perhaps. Perhaps not.

But the problem for the rest of us is that when criticism becomes the the dominant form of consumption, distillation and postulation of thought, reality takes note and tries to game it. Plucking a low hanging fruit isn’t the pluckers’ fault. This explains reactionary politics everywhere and at all times; except the degree of feedback in that loop now is far greater than it ever has been.

What does a reasonable person do, then? Wait and see if tongues and hands are cut to form an opinion? Or, be hyper vigilant about every single aspect that’s regressive in the cultural pre-suppositions of those in power? Thus wasting time that ought to have spent expanding the edifice of human thought. Or, observe the long arc of history regardless of which way it bends? What’s reasonable, therefore, appears to be held within the common sense of each strata. After all, enlightenment has always been defined as something in contrast to something else, hasn’t it? Just like teens, sometimes, want their parents to be conservative. So, there is something worthy to rebel against.

Book Review: The Fishermen

Chigozie Obioma’s debut novel is many things: part coming of age, part fable and part social commentary. But the unifying theme in all these strands is how every turn is relentlessly and seductively dark. It’s set in Akure, a town in South-West Nigeria, during the nation’s troubled 90s.

Obioma’s detailing of Akure reminds one of Malgudi. That’s a wrong reminder but a reader from Madras can’t really help being wrong in this case. There are ordinary neighbors, pastors and friends in a struggling 3rd world society. Except, this town is real. It’s dangerous. Its citizens are far more sinister and the author has no pretense of gentility. But there are boys.

Benjamin recalls the story of his childhood; narrating it as a 9 year old. He and his 3 older brothers are extremely close to each other. Their middle class parents in a poor country want them to escape that cycle of mediocrity. They are loving and occasionally show that by whipping their boys’ behinds for disobedience; they believe a Western education for their children will make them great men. Men who are lawyers, doctors, engineers and pilots.

When Father, always referred as that with a capital F, gets transferred to a different city by his employer the boys get adventurous under a lenient mother. How familiar is that to a middle class reader in India! They go fishing in the river Omi-Ala behind the Mother’s back. A river that sounds like most rivers that pass through large Indian cities: what’s become an open drain.  The 6 weeks they fish make them come into contact with the chaos and uncertainty of life. It changes their lives in horrific ways.

Obioma, to be sure, is an MFA minted in America. But the strength of his plot is a clear indication that lives elsewhere, that aren’t comfortable and white, still have arresting novelty as a possibility. The story has heavy Biblical undertones; but unlike that of the other famous MFA mint, Paul Harding, the prose doesn’t. It’s not spare though; the description of Abulu the madman’s bodily odor as a mix of uncleaned fecal matter and semen is uncomfortably vivid. The other aspect about the writing is that the most shocking aspects are quickly glossed over; it takes a while for the reader to register the scale of madness. Abulu for instance rapes his own mother and has sex with a woman who just died in a traffic accident on the streets of Akure. His penis comes repeatedly for attention; that seems suggestive of larger themes. It’s a bit difficult to get all the allusions if you did not grow up in Nigeria and are not Christian. But they still work in whatever layer you understand this work. Remarkably, Obioma manages to bring the distance and perspective of his now adult narrator whenever necessary without disturbing the conceit of the real narrator being 9 years old.

Indian writing in English is rarely any good; at least I haven’t enjoyed reading or have wanted to read one in a long while. While writing in English out of Nigeria, Zimbabwe and Somalia all seem wonderful explorations of troubled lives in struggling societies. Especially ones that seem quite similar to our own in their anxieties and structural bleakness.

More precarious than you thought

The PWD of Tamil Nadu keeps a record of Observatory Wells in each district. A comparison of the current depth to August 2010 reveals interesting trends.

Let’s look at the absolute depths for the years 2010 and 2015 (bear in mind, the Y axis is depth in meters),



As is apparent, in 5 years, 27 of the 30 regions have shown an increase in depth. Or, depletion of ground water. The extent of depletion is uneven, but if we were to average it across the state, the depletion rate is 0.34 Meters per year!



The average rate of depletion, being as high as it is, still hides how bad the situation is. The depletion is uneven as one’d expect. But what’s shocking is that the Delta region of Kaveri, starting from Trichy downstream to Thanjavur and Thiruvarur have seen their ground water levels drop by 36.41%, 52.32% and 44% respectively. In just 5 years! Some other districts you’d suspect will have depleted their ground water, such as Salem, just shock you with the scale: 59%.

The district wise depletion in ground water in percentage terms over a 5 year period is,



Chennai, perhaps because the government made rain water harvesting mandatory, has not been as bad as some of the other places. Though, it’s still lost about 15% of its ground water in that period.

This is desertification of Tamil Nadu. There’s no other way to look at it. And this also means the delta districts will have to switch to something other than paddy as their primary crop as early as possible. Importing rice, surely, is cheaper. The state cannot afford a crop that requires standing water.

The impact of ground water depletion on soil fertility in the detla region and the impact of declining quality of water on health are aspects that require further study. Hopefully someone in the Tamil Nadu government or another research institution is doing that. Let’s hope that gets published and is accessible to lay readers.

Desalination on a massive scale within 5 years will be a necessity. Perhaps Madras’ brightest are better off working on these areas compared to adding another app to the sharing economy. Surely, this will have a large enough market for most VCs, even.

Tamil Nadu’s Precarious Position

Tamil Nadu is a water deficit state. The state government acknowledges this and its own report on the extent of deficit and its impact on depleting ground water is a scary read. The  state’s water demand exceeds its known sources by 16%. If TN had a UP like population growth, it’s unimaginable what the water situation might have been. If you consider the state as an entity and compare it to that other state which is in the news for serious drought, California, Tamil Nadu is actually worse off. It’s worse off both seasonally and on a long term civilizational basis. Except water scarcity in Tamil Nadu is not the subject of obsessive focus for news outlets unlike in the Golden State.

The simple truth is: Tamil Nadu will deplete its already perilous ground water even if the rainfall is normal, given its current demand estimate. This makes “normal” a bare necessity. Now let’s look at the past two months of rainfall. The Indian Meteorological Department classifies the rainfall as normal since it’s only 5% below estimate. But that hides the real problem: the 5% deficiency is an aggregate across the state. The networks of water conservation don’t normalize water distribution like the Met Office aggregates the entire state’s data.

The deviation from the norm, if measured by each region, looks thus,

TN Rainfall


What’s striking is that the excess rainfall in just Coimbatore and Theni, both with greater than 100% excess rainfall, have had an outsized effect on the statewide aggregation. The Met Department’s own threshold of excess rainfall, greater than 20% the estimated norm, has been achieved in only 5 of the 34 regions. While 15 of them have less than 20% the estimated rainfall and are thus deficient by that yardstick. More significantly, 24 of the 34 regions have had lower rainfall than the normal.

We know that Least Mean Squared Error is a bad measure. But what this hides is so worrying. The three regions with the lowest estimated normal, Toothukudi, Ramanathapuram and Tiruppur, all have lower than the normal actual rainfall. By -29%, -42% and -13% respectively. Making the most water scarce region get worse. These regions will without a doubt overdraw their already depleted ground water.

The real question is two fold: why isn’t this on the front pages of every newspaper and why isn’t the only alternative – desalination plants – being pushed more aggressively? The cost of depleting ground water isn’t merely the absence of water; it’s also loss of soil fertility. Surely, the cost of all that when added up, makes desalination plants all across Tamil Nadu’s coastline an imperative. If Narendra Modi’s tilt to Israel has any benefit at all, let it be their expertise in desalination being brought to Tamil Nadu; not just to California.