By-law the Drive Clean program in Ontario requires an emission test on most Light-Duty Vehicles, see below;
“Drive Clean is Ontario's mandatory vehicle emissions inspection and maintenance program. It improves our health and environment by reducing smog-causing pollutants through testing and repairing vehicle emissions systems.” (Source: http://www.ene.gov.on.ca/environment/en/category/drive_clean/index.htm)
An emission test is only performed on vehicles from 1988 and newer and an emission test is performed every two years. As of September 1, 2011 an emission test will be performed for registration renewal purposes at the age of seven years, currently an emission test is performed at the age of five years.
A vehicle requires the emission test to pass or get a conditional pass to renew the sticker on the license plate.
“Effective September 1, 2011, changes to Drive Clean will save drivers time and money, while continuing to protect the environment. Learn about the changes that became law on June 1.
If your vehicle registration expires before September 1, 2011, the previous rules apply.”
“As a consumer-protection measure, an emissions test pass is required when buying or selling used vehicles with a model year older than the current calendar year, to help ensure consumers do not purchase a vehicle with emissions problems.