It is large and nothing to be proud of. But I think growth will begin to drop as we move forward. There is genune concern about the population problem as we saw the recent intitiative by Chief Justice with PM IK invited to the convention.
While thePakistani population is high but it is within certain range. For instance USA is 300 million. Indonesia, Brazil, Russia are in similiar category. But India is in stratosphere. In a league that only China can match and on way to be numer uno.
Since your Hindu and we both can agree that some humans are created more equal then others. Which is why your great civilization birthed the idea of have castes with no miscegnation to prevent blood be spoiled leading to the incredible caste system in India.
The problem you have is you have way too much lower order varnas and way too less upper order varnas. That is not good. The 1.4 billion might not be bad if it was all of noble stock but lets face it. Most of the billion is lower order varnas and you even have millions of pure sub-stock. Don't get offended. I am just playing on as 'Hindu' here.
To be sure in Pakistan we have also lower order varnas. But by grace of Allah thanks to durand Line and Jinnah our noble stock forms a good chunk of the % of the population. To put it bluntly and again as a 'honourable Hindu' Pakistan has a population with higher % of noble stock whereas India has higher % of lower order varnas. Apply that % on 1.4 billion and the results are depressing to any self respecting Brahmin.
And the greatest increase in Pakistan's population will be amongst the noble % over the next few decades but in India this is reverse. The lower order varnas will explode into even higher numbers. And I reiterate. Don't be offended. I took inspiration from Hinduism.