One of the new mechanics in Civilization: Beyond Earth is the Health system, which is similar to Happiness (from Civilization V).
Here's how it works: Health is a resource you will want to keep in the positive (appearing on the screen in green). When it's a negative (read: red) resource, cities will accumulate Intrigue faster and become more susceptible to foreign spy influence, generally grow at a much slower rate, and hamper your production speed.
Additionally, Health restricts the size and number of buildings under a player's control. However, these limitations can be countered by constructing buildings which generate extra Health. Additionally, some perks in the game will grant extra health based on certain resources, and workers can build tile improvements that can improve Health.
Now, on top of this, you can research technology that grants Health bonuses by following these steps:
- Bring up the Tech Web.
- Click on the Filter tab at the top left corner of the screen.
- Select Health.
- Let your scientists research away.