In Routine, events are either active or passive depending on their relation to your time.
All the events that you intend to attend are said to be active because those will actually consume some of your precious time.
On the other hand, all the events that you track just to be aware of them are said to be passive. Those include the events from the colleagues’ calendar that you want to track, the matches from your favorite football club or other birthday reminders. In practice, you do not intend to “attend” any of those events.
Even though it all active and passive events are displayed in the Planner screen, only active events are displayed in the 
Routine allows you to very easily define which events are active by setting some calendars as primary. On the other hand, all the events from secondary calendars are marked as passive by default.
Finally, it is possible to override these defaults by turning a specific event as active or passive. For more information, please refer to 
Contact) or through the app.