Narrative:

Approximately 3 hours into the flight; when performing pre-descent bathroom break; the flight attendants informed us of fuel/fumes smell mid-cabin over the wings near the exit row. The smell was not noticeable on the flight deck or at other locations in the cabin; and no passengers were expressing any concerns or discomfort. First officer stepped back to verify and reported it as a petroleum type smell. We contacted dispatch and maintenance via radio. There wasn't any noticeable fuel loss or fuel burn. As a precaution we placed the pack into high flow; [advised ATC]; and proceeded to ZZZ (closest suitable airfield). We reviewed the smoke/fumes checklist as a precaution in case the fumes became perceptible on the flight deck (it never did). Pilot flying donned the O2 as a precaution only. Flight attendants were instructed to review cabin prep/evac procedures but not the prep the cabin. Passengers were not informed of anything unusual/abnormal.we executed a day VMC landing at ZZZ with approach control ATC guidance. We cleared the runway and proceeded to the gate with [crash fire rescue] following.

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Original NASA ASRS Text

Title: A319 Captain reported a fume event in cruise that resulted in a diversion.

Narrative: Approximately 3 hours into the flight; when performing pre-descent bathroom break; the flight attendants informed us of fuel/fumes smell mid-cabin over the wings near the exit row. The smell was not noticeable on the flight deck or at other locations in the cabin; and no passengers were expressing any concerns or discomfort. First Officer stepped back to verify and reported it as a petroleum type smell. We contacted Dispatch and Maintenance via radio. There wasn't any noticeable fuel loss or fuel burn. As a precaution we placed the Pack into High Flow; [advised ATC]; and proceeded to ZZZ (closest suitable airfield). We reviewed the smoke/fumes checklist as a precaution in case the fumes became perceptible on the flight deck (it never did). Pilot Flying donned the O2 as a precaution only. Flight attendants were instructed to review cabin prep/evac procedures but not the prep the cabin. Passengers were not informed of anything unusual/abnormal.We executed a day VMC landing at ZZZ with approach control ATC guidance. We cleared the runway and proceeded to the gate with [Crash Fire Rescue] following.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.