Humans are on the summit of the soul's evolution from lower to higher species according to Vedic ontology. So why is the human population seem to be increasing for ever?
On the first place what is wrong in it, how does it question the Law of Karma. Besides we need to see that more humans means more consumption of livestock, more chicken and cattle (those who ate chicken in their previous lives are reborn as chicken due to law of Karma) for consumption and more mosquitoes. Who is going to account for that? And the very fact that all of the humans are somehow able to get their food itself a proof that there are more other living entities down the food chain.
The puranas talk about 8 million species of life. It is not necessary that we will have to have all the species in equal quantities. There is always a food chain and the animals consumed are always more than animals up in the foodchain. That is all. And when we see the totality of number of species all over the creation consisting of millions of universes there is no problem.
The immediate rational would be to say that the human are living longer because of better medical facilities and immunization from diseases. Which may be seemingly true. But it no way affects law of karma.
We also have to take into consideration the census methodology being adopted for estimating population. With large scale migration of people from villages to cities. There could be duplicates both intentional and non intentional. The validity can be seriously questioned. Besides in the amount of time taken to take census many people could have died. And there are so many people dying in the war torn countries, who is accounting for that.
More on myth of population explosion
ISO 1.1 In God's creation everything is perfect all imperfectness is due to imperfect living entities (read humans who disobey the laws of nature and get implicated). Besides we need to understand there is life thriving in millions of universes. An imbalance in one is nothing in the whole creation. This is not to be seen as an aberration in the laws of nature.