The Ontario Government has created a greenbelt legislation, which is surrounded by a lot of rumor and not much fact. The link (here) at least shows the maps, but is still low on information.

The concept is that urban sprawl is costing the municipalities far too much, and the developers have far too much clout in decisions regarding developing new land. The greenbelt is now protected land, and all the municipalities involved (Toronto to Niagara) will have to follow the same rules.