Once again Neptis, a pro-Greenbelt foundation says there is lots of undeveloped land.  Of course, they squeeze the facts so hard tears are coming out of the numbers.
Frist, those tiny littles specks of grey on the map are the only undeveloped land left.  There is hardly any left.
Second, Neptis is famous for talking about all the land for development in. the Greater Golden Horseshoe.  Well, who wants to commute from Peterborough or Niagara Falls to Toronto?  
Even with the land within the Greenbelt, not enough has come on the market to satisfy demand.  The problem is government that is way to slow to service land.