[{name:"Sam",specs:[{city:"istanbul",color:"purple"},{city:"istanbul",color:"black"},{city:"izmir",color:"blue"}]},{name:"Matt",specs:[{city:"istanbul",color:"blue",abc:1},{city:"istanbul",color:"black"},{city:"izmir",color:"yellow"}]}]

db.collection.find({specs:{$elemMatch:{"city":"istanbul","color":"blue"}}})