What is the scale of illegal immigration in Assam and Bengal post 1971?

Social media, dining tables and parties are agog with the CAA/CAB debate. The Govt and the opposition too have made their points. In this article, I will explore this issue purely from a numbers perspective.

Illegal Immigration into Assam and Bengal

Assam has been concerned about illegal immigration for decades now. The question is, what is the scale of immigration?

Let us begin with Fertility Rates of Some Key States (2016)

Assam: 2.3

Odisha: 2.0

Andhra Pradesh: 1.8

Bengal: 1.6

Let us look at the Population of these States in 1971 and 2011

Assam: 14.6 m -> 31.2 m, 2.1 times

Odisha: 21.9 m - > 41.9 m, 1.9 times

Andhra: 43.5m - > 84.6 m, 1.9 times

Bengal: 44.3m - > 91.3 m, 2.1 times

What stands out is Bengal. Bengal has a fertility rate lower than Andhra but its population seems to have grown at a much more rapid pace. One reason could be that Bengal fertility rates trailed Andhra marginally in the 1980s and even in the 1990s.

Assam is most intriguing. Its fertility rates are much higher than Bengal but its population has grown at the same pace as Bengal.

Now, let us look at language populations in great detail

Assamese: 8.9m -> 15.3m, 1.7 times

Odia: 19.8m -> 37.5m, 1.9 times

Telugu: 44.8m -> 81.1m, 1.8 times

Bengali: 44.8m -> 97.2m, 2.2 times

This is remarkable. I looked at the Telugu and Bengali population trend over a 40 year period

Inspite of having State level fertility rate gaps not exceeding 0.2, the Bengali population has exploded from 1981 onwards. So an almost zero gap in 1971 became a 16 million gap in 2011

Let us look at Bengali population in Assam (1971 vs 2011)

Assam Overall: 14.6 m -> 31.2 m, 2.1 times

Assam Bengalis: 2.8 m - > 9.01 m, 3.2 times

If the Assam Bengali population had grown at the same pace as Assam Population, it would have been 5.9 million in 2011. That indicates a max surplus of 3.1 million (Potential illegal migration)

Inspite of low fertility rates amongst Bengalis, the population of Bengalis has exploded versus States with similar fertility rates. This is of a particular problem in Assam.

The religious Angle

In Assam, the population of Muslims has changed as follows

Assam Overall: 14.6 m -> 31.2 m, 2.1 times

Assam Muslims: 3.6 m - > 10.7 m, 3.0 times

Bengali: 44.8m -> 97.2m, 2.2 times

Bengal Muslims: 9.2 m - > 26.2 m, 2.9 times

So it is fairly clear from all the above numbers that Muslim population in both states has exploded since 1971. However, after excluding the above 2 States, the national Muslim population has also gone up 2.8 times. If one were to apply these levels, we have a surplus Muslim population of just 2 million in these two states.

This also explains the relatively low number of people who were caught in the NRC in Assam. If we use these estimates, the Bangladeshi Muslim population would amount to 700k. The NRC number is at 800k.

So the takeaway is simple. True, the Bengali population has grown at a much faster rate than say the Telugu Population. True also, that this population is primarily on account of Muslim Bengali population. But does that translate to massive bump in Bangladeshi immigration? No!

If at all, the immigration is probably about 2 million in these two states combined.

Caveats:

1. This does not account for illegal immigrants if they are not counted in the census of Assam and Bengal. If this is large, this group may not have been counted even by the NRC.
2. The other issue is that fertility rates in Bengal are not tying in with the numbers. If the reported fertility rates are correct, Bengal surely had a large migration. But if Bengal had such large migration, its fertility rate should have gone up because Bangladesh fertility rates have been higher than Bengal throughout this period.

A little bit of background on which are the other demographic groups that have grown substantially since 1971

Scheduled Tribes: 2.9

Muslims: 2.8

Hindi Speaking Population: 2.6

Scheduled Castes: 2.5

India: 2.2 times