Compulsory voting , 22 countries were recorded as having compulsory voting. Of these, only 10 countries (additionally one Swiss canton and one Indian state) enforce it. Of the 30 member states of the Organisation for Economic Co-operation and Development, 10 had forms of compulsory voting. These are the countries and sub-national entities that enforce compulsory voting: Countries that have compulsory voting by law but do not enforce it: Although voting in a country may be compulsory, penalties for failing to vote are not always strictly enforced. In Australia and Brazil, providing a legitimate reason for not voting (such as illness) is accepted.
Catalytic converter oxides of nitrogen, they were superseded by three-way converters. Three-way catalytic converters (TWC) have the additional advantage of controlling the emission of nitric oxide (NO) and nitrogen dioxide (NO) (both together abbreviated with and not to be confused with nitrous oxide (NO)), which are precursors to acid rain and smog. Since 1981, "three-way" (oxidation-reduction) catalytic converters have been used in vehicle emission control systems in the United States and Canada; many other countries have also adopted stringent vehicle emission regulations that in effect require three-way converters on gasoline-powered vehicles. The reduction and oxidation catalysts are typically contained in a common