Dude(I hope you are,or else Ma'am), HongKong is an urban conglomerate(yes it is independent region). It is a city you can't apply the same logic of cities to a an entire nation.My point is still valid.
WHAT point? Dude, you need to spend some time with gapminders.org . Follow the links below and press the "play" button beneath the charts.
India and Bangladesh have in the last few decades had a rapidly falling birthrate (down to around replacement level) along with rapidly improving child mortality rates. Watch this in the form of blue dots marching down and to the left.
> So where's the impending disaster? I don't see it in any of the relevant metrics.
The impending disaster is in its early stage and is slowed down a bit due to mass immigration of Bangladeshi citizen into neighboring countries and rapid urbanization of India (specially western and southern India) and please check the number of immigrants of bangladesh and hazardous urbanization of India.