ADR27A was an Australian Design Rule specifying design and operating regulations to limit fuel evaporative and exhaust emissions for motor vehicles in Australia in order to reduce air pollution. The rule covered "all motor vehicles specified below (see ) equipped with petrol fuelled spark ignition internal combustion engines except those also equipped to use use liquified petroleum gas (LPG) and those with and engine displacement of less than 850 millilitres (850cc), manufactured on or after 1 July 1976."