Idle Population refers to the number of residents that are not employed in your city. Although not working, they still contribute tax to the city and they are used to train new troops.
When your idle population is negative, it means that you do not have enough population to man all of your resources and troops. As a consequence, your resource production will be reduced until you increase your population. You will not be able to train troops with a negative idle population.
How do I increase population?
To increase your general population:
- Create or upgrade homes to increase the maximum limit.
- Lower your tax rate to attract more people to your city. Take into consideration that once positive conditions are met, your idle population returns. To alter your taxes, just tap on the "city status" bar (the bar where your current resource count is shown), tap over to "Taxes" and change however you'd like.
- Certain general skills can help. Generals like Gralix have the skill "Increase population limit". These skills only work when the general is assigned so make sure you assign those generals! These skills can be leveled up to be more effective.
- The great dragons' buff also adds an extra 20,000 OR more! Depending on if you have an "increase population" skill active on an assigned general. You can unlock this when your dragon reaches level 20. The skill can be acquired from dragon explorations, arena store, dragon battle ground (dependent on realm/age) and rubies.