Can I say,
1 The school wants to teach the pupils how to recycle the recyclable items.
2 The school wants to teach the kids on how to do recycling/ recycling activities.
#1 has unnatural repetition. #2 is OK. Better is #3 The school wants to teach the kids how to recycle.
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#1 has unnatural repetition.
#2 is OK.
Better is
#3 The school wants to teach the kids how to recycle.