which part dont you understand. it obviously from a piece of fiction. the author is trying to paint a picture drab is used to describe the building as dull, depressing, grey.

A beautiful sentence: IN a drab (grey/merky) concrete building on the southern fringes (southern edge/borders) of Tehran a woman’s voice gently (softly) pierces the air (breaks the silence/rings out above other noise/cuts through the air), rising to a lingering (continuous) vibrato (a trilling/vibrating sound/muscial note made with the voice or a musical intrument).