NO, 'not pulled out of a hat'.....those figures are concluded from direct population surveys....see the link below...
Illegal immigration: East Bengal in West Bengal : The Big Story - India Today
Read what your first source said again , the gov of India does not have accurate info on illegal immigration. Dead in the water.
Any figure you therefore spurt out is therefore not accurate and can be disregarded. I've read your second source can't see anywhere where it states a figure of 20 million. Please point it out for me.
Secondly please stop being selective in what you answer.
Thirdly please explain this, you stated that these imaginary 20 mil illegals have no money live in slums and are too poor to build toilets. Now lets say we use your unreliable inaccurate figure and there are 20 million illegals in India, your now assuming that all these 20 million poop like their fellow 630 million Indians outside in the open because of poverty ( the rest of the Indians are civilised and have shame). Any proof of this? Poverty clearly has nothing to do with shitting in the open. Even poor people can shit indoors in a bucket.
To further prove to you my point the poverty rate of India according to world bank in 2010 was 29.8% and in 2012 21.9% and Bangladesh was 31.5% in 2010 (there are no 2012 figures).
So if like you say poverty is leading to all of the imaginary 20m pooping why even though the fact that Bangladesh has a higher lever of poverty than India as a whole, does it totally destroy India in terms of open defection rates 3% vs 50%????.
None of your arguments hold any weight and it is clear to see.
Accept your problem and deal with it, the issue with The 630m Indians that openly defacate is that mist still do it even if they have toilets as per the study posted by soms a couple of pages back. At least the imaginary 20million illegals according to you can't afford to build toilets , these Indians do it even when they have toilets!
I don't see why a percentage of Hindus think having a toilet in their home is dirty, it is much cleaner than pooping outside. The faeces will be flushed down the toilet and that's the end of it. Use toilet tissue, lota/bodna and some liquid and that's it! The video is a good step in this regard more needs to be done.