This purely hypothetical solution dose not account for very real-world consequences / draw backs. However, in the spirit of making the world a better place, I’m going to toss all of that out the window.
Deep space travel has given rise to some very compelling research in the field of “human hibernation”. The motivation behind this, as just stated, is obviously being, ‘extended space travel’. What if we applied that to over population?
By Creating a rotating society in which 1/3 of the population would be in ‘short term’ hibernation. We could cut down the pollution from daily commuters by 1/3. Save 1/3 of the food supply, use 1/3 less real estate. What if you could cut down on daily spending by 1/3? How much would you save?
I'm not proposing a we snap our finger and whisk away 1/3 of the population (that didn't even workout in the movies). Rather use up and coming tech to responsibly manage our resources by going to sleep for a day or two.
Granted, were not quite there yet, but I could see this being a viable solution to not just one issue but many.
The real fun part is trying to figure out how three groups of people could manage to see one another, all at the same time, while being on rotation.
This is more of an idea rather then a project, but small changes can make a huge impact when scaled up.