Really? Try saying that to the starving millions in Africa and India.
That's the trouble with you younger people. You have not experienced hunger, and thinks more mouths to feed is better. That's the same way India is thinking.
India is not China.
Firstly, India has the caste system which will constrain itself from becoming as powerful as China; purposefully hobbling a significant proportion of your own population just to maintain your own familial privileges is a recipe for disaster. Thankfully, China has done away with that. And even without the caste system, the malnourishment and vegan diets of indians prevents them from forming the brain capacity to innovate compared to the indians who come to the west.
And on that matter, compared to the 70s and 80s, China has secure food security and food production; the only thing China currently lacks are tertiary education facilities for its growing middle class, hence why you have a lot of chinese students going to the west to study. This will be solved in time as graduate staff return to China and take up positions at homegrown universities, or new universities are set up. In fact, the advent of COVID has made studying from home more prevalent and hence softening the need for universities.
Please read some economic 101 before coming on here to show your ignorance.
1st. Aged people are consumers.
2nd. Aged people are also tax payers.
Not if they rely on the age pension, then they simply become consumers and even then they don't consume as much as DINKs or families.
More kids will alleviate that problem, even if that means more applicants, and more competition for jobs; you can't expect to shield your kids form competing with the world, the way some asian parents emigrate to the west because they find that their formerly average student can become an A class dux of the year in a crowd of lazy western kids.
What China doesn't need is a welfare society in the manner of sweden or the UK where it accepts immigrants who don't contribute, don't speak the language, and take welfare monies as a new consumer class.
More Chinese people means more probability of scientific and tech minds to solve these environmental problems (especially since the Chinese society, culture and family ties promote a pro-social and pro-scientific/intelligence/education outlook).
It also means more PLA troops to take control of Australia and North America and the subcontinent of India, but that's for another thread.