The Vedic literature tells us that there are 8,400,000 species of life, and living beings pass through all of them. So although to our limited vision the population may be growing, when we take all these species into account the true population of the world is beyond counting.
Added to this, the Vedic literature tells us that there are also living beings on other planets and in other universes.
The results of our limited human census, therefore, don’t present a problem.
One might object that this is just an ad-hoc explanation, a cop-out, a way to escape from the objection. But in fact it is an integral part of the Vedic philosophy, with implications in other contexts That it is not falsifiable doesn’t mean that it’s wrong. The realms of empiric science have their limits, so not everything in the world is falsifiable. What it means, therefore, is that the truth of this Vedic teaching is beyond the ability of science alone to either confirm or deny.