Pointing to Priya, father of Pritu says, "She is the daughter of the only…

In multi-generation blood-relation puzzles, convert a chain of descriptive clues ("the wife of the only son of...", "the only daughter of...") into an actual family tree, one generation at a time, until the elaborate description collapses back onto a relative the speaker has already named directly. Track carefully whether each step moves UP a generation (father, grandfather), STAYS level (wife, brother/sister), or moves DOWN a generation (son, daughter) -- a single missed generation flips the final relationship.

1. Let X be the speaker, the father of Pritu. Y = X's father's sister -- X's paternal aunt, one generation above X.

2. "The grandfather of Y" is Y's father's father. Since Y is the sister of X's father, Y's father is X's grandfather, so Y's grandfather is X's great-grandfather.

3. English "grandfather" doesn't by itself distinguish paternal from maternal; as a standard solving convention for this puzzle genre, we take the reading that folds the chain back onto a relative already named in the sentence (the aunt) -- this is an assumption, not a fact stated outright in English, though the accompanying Hindi wording ("दादा") specifically means the paternal grandfather and removes this ambiguity.

4. "The only son of" that great-grandfather must be X's grandfather himself -- he is the great-grandfather's son, and the clue says he was the only son.

5. "The wife of" X's grandfather is X's grandmother.

6. "The only daughter of" X's grandmother is her only daughter. Y is independently confirmed to be a daughter of X's grandmother (Y is the sister of X's father, so they share the same parents) -- and since the clue tells us there is only one daughter, that only daughter must be Y herself. The chain has folded back onto Y, the aunt already named in the sentence.

7. "The daughter of" Y is Priya. Since Y sits one generation above X, Y's daughter Priya sits in the SAME generation as X -- Priya is X's (Pritu's father's) first cousin through the paternal aunt.

8. Pritu and Sushma are X's own children, one generation below X. Since Priya is level with X and Sushma is one generation below X, Priya is one full generation above Sushma.

9. A person one generation below, connected through the cousin/aunt line, is a niece. So Sushma -- one generation below Priya -- is Priya's niece.

Cross-check: the descriptive chain deliberately reduces step by step back to "my father's sister" -- a person already named in the statement. If the chain instead reduced to "my sister" (X's own sibling, not X's aunt), Priya would land in the same generation as Pritu and Sushma, making them cousins -- but the statement clearly says "my father's sister," not "my sister," which is the one extra generation that changes the answer.

Priya is one generation above Sushma and Pritu, so the correct relation of Sushma to Priya is niece.