Unite is a type of Change. Pair is a type of Unite. Couple is a type of Pair. 
Waste is related to Excessive. Excessive is the opposite of Conservation. Conservation is the opposite of Pollution. Pollution is related to Smoke. 
Change <--IsA-- Unite <--IsA-- Pair <--IsA-- Couple 
Waste <--RelatedTo--> Excessive <--Antonym--> Conservation <--Antonym--> Pollution <--RelatedTo--> Smoke 