So the provincial government had an existing law that prevented the use of "renewable energy" systems from being blocked by local by-laws and such. So they classified clothes lines as a renewable energy system so people could use "solar power" to dry their clothes as a energy conservation mechanism.
> "There's a whole generation of kids growing up today who think a clothesline is a wrestling move," [Premier] McGuinty said during his announcement.
* https://toronto.ctvnews.ca/ontario-premier-lifts-outdoor-clo...
The current Ford government repealed the law that allowed for this, so I'm not sure what the legal status is now exactly.