Why do I see charging stations flagged in different colors on the map?

The status of every station is indicated by a different color with a badge on the marker:
● Green: At least one of the plugs is available for a use
● Red: All the plugs are currently occupied or reserved
● Grey: The station is undergoing maintenance and is not available
By clicking on the charging station, you can see in detail which plugs are occupied, reserved, or free.