What kind of context clue is "The hotel abolishes
its rice-all-you-can policy to avoid wastage of food"?

Contrast or Antonym Clues

Explanation:

Finding the "context clue" is important in order to know the meaning of a sentence. There are several types of context clues and these are: Definition/Explanation Clues, Restatement/Synonym Clues, Contrast/Antonym Clues, Inference/General Context Clues and Punctuation.

The example sentence above uses the "Contrast/Antonym Clues." It used the word "avoid" which gives you a clue that the meaning of the sentence is opposite to "wastage of food." So this means that "rice-all-you-can policy" is a wastage of food, thus it has to be abolished.