Sudbury (pop. 88,700), city in Ontario, Canada. In 1883 rich deposits of copper and nickel were discovered there by workers building the Canadian Pacific Railway. Since the early 1900s, Sudbury has been a major producer of nickel for the world. Sudbury also produces most of the copper used in Ontario. Other metals mined there include gold, silver, platinum, and iron ore. The city suffers from heavy concentration of air pollution created by the metal plants. To help spread the pollution over a greater area, one mining company built a smokestack 1,250 ft (381 m) high—the tallest one in the world.
See also: Ontario.