Toronto

Toronto was a city in Canada.

In 2006, standpipes and water rationing were used in Toronto, as water shortages were common due to environmental damage. (NA: Iceberg)

In the early 21st century, Baskerville predicted that a nuclear device would accidentally detonate in Toronto, destroying the city, but the Eighth Doctor prevented this. (EDA: Trading Futures)

In 2040, the Doctor helped stop a terrorist group from blowing up a nuclear power plant in Toronto. (ST: The Nuclear Option)

During the mid to late 20th century Toronto was a primary hub of the T-Mat network. (DW: The Seeds of Death).

The colony world Toronto was presumably named after the city. (PDA: Ten Little Aliens)

Behind the scenes
Doctor Who creator Sydney Newman was born in Toronto, where he also died.