The Clue "___ This Kolaveri Di?"
The Answer WHY
The answer to the crossword clue "___ This Kolaveri Di?" is "WHY." This fits because "Why This Kolaveri Di" is the title of a popular Tamil song. The song became famous for its catchy tune and humorous lyrics. Using "why" in the title expresses curiosity and confusion, which is central to the song's theme.