From a wikipedia article I was reading:
L'escadre française commandée par le contre-amiral Louis Dubourdieu bombarde la ville jusqu'au lendemain en détériorant sérieusement les infrastructures de la ville, dont la Grande Mosquée qui est gravement touchée.
I don't understand the purpose of qui. I would have just written it as "dont la Grande Mosquée est gravement touchée," as in "whose Grand Mosque was strongly affected." (roughly)
While I still understand the sentence's meaning, I don't understand why qui is grammatically needed here.