I looked up the thing I was quoting from top of my head from:
International Migrant Stock 2020 The estimates of the number (or “stock”) of international migrants disaggregated by age, sex and country or area of origin are based on national statistics, in most cases obtained from population censuses. Additionally, population registers and nationally...
www.un.org
From 2019 excel sheet (covering years 1990 - 2019)
The estimates:
Born in BD, living in India:
1990: 4.4 million
1995: 4.1 million
2000: 3.9 million
2005: 3.6 million
2010: 3.3 million
2015: 3.2 million
2019: 3.1 million
Born in India, living in BD:
1990: 13k
1995 - 2015: gradual increases
2019: 35k
So as you can see there is a natural population decrease over time estimated.....both by BD improving economy (to demand pull BD people back.retain to homeland etc, where they are also more secure socially, especially if more recent/transient in migration time and also the excel file shows increase into gulf countries as well from BD labour) and also natural population decline of the original large stocks that moved during partition and then from 1947 - 1971 and then the 1971 period itself with huge upheavel.
Downstream to that to present day would be whatever flux in another layer of folks (to these large earlier stock).... largely economic driven in comparison to safety/refuge driven etc.
It is of course a complicated long topic affair,
@Joe Shearer probably can add some details if he is so inclined:
en.wikipedia.org
(has some estimated numbers etc)
With new citizenship laws in India, the refugee is being used to determine the Indian citizen along religious lines. Ria Kapoor looks at how Partition in 1947 and the Pakistani refugee crisis of 1971 are shaping this process of…
www.historyworkshop.org.uk
Quotes:
The issue/estimates just in assam (a hot button topic well before BJP got its current power there, infact BJP used this existing issue to break off certain congress party people that were vested on the matter to gain power and retain it to large degree now in Assam, i.e the issues were well known during congress et al tenures before):
en.wikipedia.org
(summary of some deep underlying reasons that come about by sudden hard border during partition, with some estimated numbers and then populist reactionary politics to it)
Anyway, all are estimates ofc, there would be some +/- on top, but is it really a top level issue that ought to be put front and centre for IND-BD socioeconomics and politics to whichever degree it is now? Better policing would deal with any criminal and security elements better, that should be priority even with no hard border to begin with.
If I were cloned 10,000 times over to run Indian (and BD if you would have me) top level politics, it would be very different picture in end.
i.e the <10 k per capita effect (too much bark politically compared to bite given actual reality people want to not process first....i.e the feature with politics broadly with negativism/fear harnessed first and most easily) I mention in the BD economy thread posts.
i.e BD people at large (and its politicians as much as they can afford to, rather than falling for "the trick/game nasties" themselves) are best off filtering first thing, is it sanghi/bhakt indian vs other type of indian and listening to and working with other type as far as possible. The vice versa of this too for Indians and filtering out the fringe jamati or bad faith Bangladeshis towards India.
That way you have larger basis of realistic, genuine stuff at the base level that will hopefully over time do its thing to get rid of nasties that percolate and get amplified for foul purpose at top level politics, reactionary and counter-reactionary stuff here....with no clear chicken and the egg resolution but rather simply might makes right that exists with the basic total 7:1 ratio IND enjoys over BD.
But its all easier said than done, things get amplified as they do for politics.
In BD, IND context, the basic rub is that both need to get to >10k per capita to really come to terms on this migration topic to begin with.....as right now its splitting hairs on sad predicament of our 90% population and how they adjust to shocking lack of development (as my core latent take as secular right winger overall, I often summarise it as total dereliction over long time of the supply side economics in the region, so everything has turned into scarcity and price levels w.r.t demand side from the larger population wants and needs...and then the surplus time that needs to be dispensed somewhere....scapegoating, fear, anger etc on someone different enough having their bit of the alloted pie and making do)
This is done by powers that be often for (or lending further to) express status quo partisanship in politics to turn people against one another (in most unfair wedge issues and harnessing of all kind of social conservative angst for zero sum/fear/anger application) and keep them weak for benefit of the 10% and 1% etc.