Lost over 600 citizens overnight

[Ram Rod]

My nation lost over 600 citizens overnight. My nation had an earthquake event which was said to loose -$5.00 income per citizen. I purchased improvements of 1-bank and 1-school to make up for that, but the income level has dropped significantly anyway. What actually happened here? It appears my improvements haven't taken effect?

[Mark Reynolds]

You have an open trade slot, so it might be that you have lost a trade partner without realising it. The game doesn't always inform you when you lose a trade partner, so this is an easy thing to miss; I've done this myself a few times

[Count Rupert]

Yes it could be a lost trade; you only get notification when a trade partner manually cancels the trade. If the trade partner is deleted for infractions or inactivity, you receive no notification. Also there was a fairly large spike in the Global Radiation Level which affects your environment (which affects both population (but not by 600 though) and happiness), that could to blame as well.

[thedestro]

You also could have had an expired event.

[Botha]

Looking at your nation profile and your citizen count, my guesses are you either lost a fish and/or a wheat trade or the event (refugees flooding into your nation) which I think boosts your population by +10% expired overnight. You can check events and their expiration dates in "events" under "nation menu"