Mathieu Laberge, the CMHC’s chief economist, wrote that there are two other key factors that have slowed the housing supply in Canada. First, many of this country’s major cities, notably Vancouver and Montreal, have mountains and waterways that are natural barriers to the construction of new houses. Second, Canada has fewer large cities than the U.S., leaving urban residents with fewer places they can move to find comparable jobs, thereby triggering new developments.