decrease vs wastage

decrease and wastage both are nouns.

Word	Noun	Adjective	Verb	Adverb
decrease	Yes	No	Yes	No
wastage	Yes	No	No	No

As nouns, wastage is a hyponym of decrease; that is, wastage is a word with a more specific, narrower meaning than decrease:

Other hyponyms of decrease include decay, decline, decline, diminution, desensitisation, desensitization, narrowing, slippage.

decrease (noun)	wastage (noun)
the act of decreasing or reducing something	anything lost by wear or waste
the amount by which something decreases	the process of wasting
a change downward
a process of becoming smaller or shorter

decrease (verb)	wastage (verb)
decrease in size, extent, or range
make become smaller