Complex sentence: As of February 2017, increasing numbers of refugees are crossing the Canadian border from the US without presenting at a border crossing in order to avoid the effects of the agreement which would required the refugees being turned back to the United States.
Split into simpler sentences: As of February 2017, increasing numbers of refugees have been crossing the Canadian border from the US other than at a Canadian border crossing point. This is in order to avoid the effects of the agreement, which requires refugees presenting at a border crossing to be turned back to the United States.