What is a 'Non relevant sub topic'?
This sounds serious!!It can be.
You need to keep your sub topics relevant to the Main topic.
It can be about you but...
Example - your sub topics could be about your Consumption and how you can
Reduce your waste
Reduce your water usage
Travel more ecologically
BUT NOT..
Sub topic 1 - Save the Whales
Sub topic 2 - Save the glaciers
Sub topic 3 - Save the Turtles