Before we begin our discussion, just spend a little time and think about this map of India.
Religions map of India. Hindu (79.8%), Muslim (14.23%) Christian (2.3%), Sikh (1.72%), and Buddhist (0.7%) etc. With this being the religious demography of India, some people can actually believe and argue that Hindus are in danger in India. [Wikipedia]
With this being said, let us begin. India is a Hindu majority country. Here 79.8% of the total population are Hindus. Other religious communities like Muslims, Christians, Sikhs are at 14.23%, 2.3%, and 1.72% respectively of the total population. Thus Hindus are by far the dominant religious community in India.
Among all 35 states and union territories, apart from states like Arunachal Pradesh (Christan), Jammu and Kashmir (Muslim), Lakshadweep (Muslim), Meghalaya (Christian), Mizoram (Christian), Nagaland (Christian) and Punjab (Sikh), Hindus are in majority.
But still, on many occasions, I have heard people make claims like “हिन्दू खतरे में है!” (“Hindu is in danger!”). Another very common saying is that by 2050 Hindus will be in minority and Muslims will take over as majority. If at any point anyone asks someone who espouses such a belief, “Why do you think that Muslims will overtake Hindus even though they are even less than 15% and Hindus are at a whopping 80% of the population?” Among all the answers I have seen, there is one very common feature of the argument which is that the population growth rate of Muslims is very large compared to Hindus.
From my understanding of mathematics and looking at the national census data, I could never understand how in reality people can believe such a thing? Below I am going to discuss four different models of future population growth for Hindus and Muslims in India. From these models, we will examine the projected total populations of the two religious communities for the next one and half-century, i.e. up to 2171 AD.
Before we begin, let us understand two very important terms for this discussion! And these are:
- Growth rate: This term means at what pace a population is increasing. Because in India, the census is conducted every 10 years, so the rate of population growth or simply growth rate is measured on a decade basis. For example in the 2011 census, the rate of growth for Hindus and Muslims was respectively 16.76% and 24.60%. This means that from 2001 to 2011 Hindus population increased by 16.76%, i.e. if somewhere there were 1Crore Hindus in 2001, then in 2011 there the population must have increased to 1Crore 16 Lakhs 76 thousand people.
- Rate of change of growth rate: This term means that how the growth rate is changing with time. For example, in the 2001 census, the growth rate for Hindus and Muslims was respectively 19.92% and 29.52%, while in the 2011 census the respective growth rate decreased to 16.76% and 24.60%. Thus in the decade of 2001-2011, the rate of change of growth rate for Hindus was (16.76-19.92)/19.92=-0.1586… i.e. negative 15.86%. Similarly, in the same decade of 2001-2011, the rate of change of growth rate for Muslims was (24.60-29.52)/29.50=-0.1668… i.e. negative 16.68%. Thus both for Hindus and Muslims, the rate of increase in population has decreased (negative) and that decrease is 15.86% for Hindus and 16.68% for Muslims. Furthermore, the rate of population growth for Muslims has decreased more compared to Hindus and this fact is in stark contrast to the belief that “हिन्दू खतरे में है!”
MODEL 1 — Constant Growth Rate as The 2011 Census
Now, let us begin with our first model. Here let us consider that the growth rate would not change (i.e. the rate of change of growth rate is zero). In more explicitly saying, we are assuming that for the next one and half-century the Hindu population will grow at 16.76%, while the Muslim population will grow at 24.60% (both same as the 2011 census rate). In the following figure, we see the projected populations for Hindus and Muslims.
It is clear that even with a higher growth rate (24.60%) the Muslim population still remains less than half of the Hindus (lower growth rate 16.76%) even after one and a half-century. And this is because the Hindu population is very high, to begin with in 2011 compared to Muslims.
MODEL 2 — Growth Rate Decreases as The 2011 Census Rate of Change of Growth Rate
Here let us consider that during every coming decade, the growth rate decreases with the same negative rate of change of growth rate as in the 2011 census. As we have discussed above that the population growth rate has decreased by 15.86% for Hindus and 16.68% for Muslims during 2001-2011, so in our second model, we will consider that in each decade the population growth rate also consistently decreases by 15.86% for Hindus and 16.68% for Muslims. In the following figure, we see the projected populations for Hindus and Muslims according to our second model. It is still a relief that according to this model, our population will plateau and will not increase further by 2171. This is because with decrease in population growth rate in each decade, by 2071 the growth rate becomes nearly zero!
Its clear that even if the population dynamics (the decreasing population growth rate) of the last decade is maintained for the next one and half-century, the Muslim population remains well below the Hindu population. The contrast is so much that even in 2171, the Muslim population will remain less than the population of Hindus right now!
MODEL 3 — Growth Rate Decreases by a Constant Factor
In this model, let us now consider that the population growth rate decreases not according to the 2011 census rate but by a constant factor of 5%. For example, during the 2001-2011 growth rate has decreased by 15.86% for Hindus and 16.68% for Muslims, but in this 3rd model, we are considering that both the Hindus’ and Muslims’ growth rates will decrease by the same factor of 5%. Thus in 2011, the growth rate of the Muslim population was 24.60% and hence in 2021, it will decrease by 5% to 23.37%, in 2031 it will become 22.20% and so on. Similarly, in 2011, the growth rate of the Hindu population was 16.76% and hence in 2021, it will decrease by 5% to 15.92%, in 2031 it will become 15.13% and so on (see the lower graph below).
As it is again clear that in this model of population growth too, the Hindus remain in the majority forever, even though the Muslim growth rate remains higher than that of the Hindus. In 2171, the total Muslim population still remains less than 40% of the Hindu population.
MODEL 4 — Growth Rate Increases for Muslims’ and Decreases for Hindus’ by a Constant Factor
In this model, we are considering a situation where the growth rate for the Muslim population only increases by a constant factor of 5% in each decade starting with the 2011 growth rate of 24.60%. Whereas the growth rate for the Hindu population only decreases by a constant factor of 5% in each decade starting with the 2011 growth rate of 16.76%. As can be seen from the following figure, according to this model of population growth, the Muslim population will indeed surpass the Hindu population by 2121. This is an utterly unrealistic model because in this world this is never going to true that the Muslim population’s growth rate is only positive and that of Hindus is negative. As we have seen at the beginning of this discussion that already during the 2001-2011 decade, the Muslim population’s growth rate decreased by the highest amount (16.68% from 29.52% to 24.60%) in the history of the census of India.
According to this model, clearly, the Muslims replace the Hindus as the majority population in India by 2121. But in reality, unlike what we have considered here, the population growth rate is universally decreasing throughout the whole world. The rate of the decrease is only different for different communities and in a different country, which depends on the literacy level, health, and economic stability.
Conclusion
As can be seen from the different models above that there is no such realistic scenario where the Muslim population is going to surpass that of the Hindus’. In only the last model, we may see a situation where Muslims may become the majority in India leaving behind the Hindus, but the assumption of this model completely defies all the data that we can find so far from the previous census and also from the population trends from all over the world. So to conclude, this is absolutely absurd to claim that “हिन्दू खतरे में है!” (“Hindu is in danger!”) in the sense that Hindus may become a minority population in India. Of course, there are many other situations where indeed “हिंदुस्तान खतरे में है! (India is in danger!)” and we have to deal with those dangers firmly with all Indians together, no religion should come in between to divide us.
The π life - Walk to Infinity 
I am sorry Mr Deb. But you are just plain wrong. assuming Muslim population is 20% for simplicity and also the fact it has been growing since the last census and we have significant amount of illegal bangladeshi population unaccounted for in the census. With that assumption and the constant rate of growth for both population,, if I do the calculation,. after approximately 17 decades hindu and muslim population will be equal. after that muslim population will overtake assuming constant rate of growth. If I assume the rate of growth slows down at the same extend every decade for both populations, even then Muslim population will overtake Hindu population sometime, but significantly further down in time.
Initial Hindu Population = 104 == H0 (in crores)
Initial Muslim Population = 26 = M0 (in crores)
Total Initial Population = 130 (in crores)
Hindu population growth rate = 15% per decade
Muslim population growth rate = 25% per decade
Hindu population after 1 decade = 104 * (1.15)
Hindu population after n decades = 104 * (1.15)n
Muslim population after 1 decade = 26 * (1.25)
Muslim population after n decades = 26 * (1.25)n
104 * (1.15)n = 26 * (1.25)n
4 * (1.15)n = (1.25)n
4 = (1.25)n / (1.15)n
Ln (4) = n * ln (1.25/1.15)
1.386/ 0.083 = n = 16.78
sorry the superscript and subscript dont show up properly when I copy paste from my word. So assume 0 is a subscript in H0 and n is a superscript in (1.15)n
Sorry the superscript and subscript dont show up properly when I copy paste from my word, for some reason. You know which one is subscript and which one is superscript, I am sure.
Thank you for your interest.
In your calculations, you missed the power of compounding. When you write, “Hindu population after n decades = 104 * (1.15)n”, you are wrong because every year the population increases not as a multiple of the initial base (in your case Ho=104). Rather, the population increases in a compounding manner. And that’s why Hindus add way more population than Muslims because the starting Hindu population is huge in comparison.
Once upon a time Indonesia Reached 30% Muslim Population It was immediately declared Islamic Country. Like you peoples will surely Make India very soon Islamic country by such nonsensical Articles.
By training, I am a student of Science. So if you could explain which part of my article/data/calculation is “nonsensical”, I will be happy to change my conclusion.
I have a feeling you have no understanding compounding at all. 1.15 to the power of n is that compounding. Have you not seen the formula for calculating compound interests? A = P(1+r)^n, where r is the annual interest rate and n is the number of years assuming interest only compounds every year, just to simplify that calculation. if you assume r = 15% or 0.15, you will get P (1.15)^n. That is precisely what I am doing. Instead of P being principal money vested, Ho as you call it is the base population. 1.15^n takes care of the compounding. I think you really ought to learn basic mathematics
Dear Shiv,
Yet again, the culprit here is the “copy-paste”! In your first comment, the ^ (power sign) was not there and I went with your calculation “Hindu population after n decades = 104 * (1.15)n”, i.e n being multiplied and not placed as “power”. And honestly, just now I realised that you already mentioned this as a “copy-paste” error in your second comment. Carelessness on my part too.
Coming back to your calculation, going exactly according to 2011 census data, the decade when Muslim population will cross Hindu population in India is, n = ln(96.56/17.22)/ln(1.2460/1.1676) = 26.529 i.e. after around 265 years from 2011.
Now, the dangerous problem with this simplified calculation is that the population growth rate is considered to be constant and we know this is not true. Both for Hindus and Muslims, the rate of growth is negative, and importantly, it is more negative for Muslims (-16.68) than for Hindus (-15.86%). And this negative population growth is a global phenomena, and there are many factors for this slowing down of population growth rate. Some of the major factors are education, urbanisation, access to better health and information, etc. So, when we consider the negative growth there is no way the Muslim population can become higher than Hindu population in India.
And lastly, I believe being respectful is a virtue. This conversation would have been much enjoyable, if you had avoided those negative remarks and judgement in your comment (especially when you even do not know me!). Peace.
I have a typo above. the formula should have n-1 in the exponent instead of n. But you know that.