If you're having all of the required documents handy with you including the PCC, then you can submit your application by sitting anywhere in the world. If not, then you don't have another choice. Besides, you'll have to return back to your home country for the passport submission for the PPR thing.
Note: in some cases, few of the documents need to be notarized, which means stamping and authentication needs to be done from your respective nation only.
Further doubts can be cleared by approaching some consultations!