Slitherine

If you conquer a city and it's pop-growths is less than -1 then setting the city to selfdestruct can significantly slow down the loss in population.

For example: A freshly conqured size 27 city has -4 pop-growth per turn usually. Until it recovers you lose about 20 pop.
If you set it to selfdestruct instead you only lose 1 pop per turn. And when it recovers you may have lost only about 8 pop.

So if both: Self-destruct and negative growth are active at the same time the one that is more effective shall count. Or they should be added together.

Halfing migration moves the amount of population where the exploit becomes effective. It doesn't solve the inheritent problem!
The solution would be adding migration and raze-effect if both it active at the same time.

Here's 2 more screenshots:

1. Takeover migration:

2. Pop-loss due to raze:

The latter is way lower. And it saves a lot of food on top of that.