Roof is related to House. Sky is etymologically related to House. you are likely to find Pollution in/at/on Sky. Pollution is the opposite of Conservation. 
Genre is a type of Art. Art is related to Inspiration. 
Roof <--RelatedTo--> House <--EtymologicallyRelatedTo-- Sky <--AtLocation-- Pollution <--Antonym--> Conservation 
Genre --IsA--> Art <--RelatedTo--> Inspiration 