Emission standards are the legal requirements governing air pollutants released into the atmosphere. Emission standards set quantitative limits on the permissible amount of specific air pollutants that may be released from specific sources over specific timeframes. They are generally designed to achieve air quality standards and to protect human life. Different regions and countries have different standards for vehicle emissions.

Regulated sources

Many emissions standards focus on regulating pollutants released by automobiles (motor cars) and other powered vehicles. Others regulate emissions from industry, power plants, small equipment such as lawn mowers and diesel generators, and other sources of air pollution.

The first automobile emissions standards were enacted in 1963 in the United States, mainly as a response to Los Angeles' smog problems. Three years later Japan enacted their first emissions rules, followed between 1970 and 1972 by Canada, Australia, and several European nations.[1] The early standards mainly concerned carbon monoxide (CO) and hydrocarbons (HC). Regulations on nitrogen oxide emissions (NOx) were introduced in the United States, Japan, and Canada in 1973 and 1974, with Sweden following in 1976 and the European Economic Community in 1977. These standards gradually grew more and more stringent but have never been unified.[2]

There are largely three main sets of standards: United States, Japanese, and European, with various markets mostly using these as their base.[2] Sweden, Switzerland, and Australia had separate emissions standards for many years but have since adopted the European standards. India, China, and other newer markets have also begun enforcing vehicle emissions standards (derived from the European requirements) in the twenty-first century, as growing vehicle fleets have given rise to severe air quality problems there, too.

Vehicle emission performance standard

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An emission performance standard is a limit that sets thresholds above which a different type of vehicle emissions control technology might be needed. While emission performance standards have been used to dictate limits for conventional pollutants such as oxides of nitrogen and oxides of sulphur (NOx and SOx),[3] this regulatory technique may be used to regulate greenhouse gases, particularly carbon dioxide (CO2). In the US, this is given in pounds of carbon dioxide per megawatt-hour (lbs. CO2/MWhr), and kilograms CO2/MWhr elsewhere.




From 1 January 2024, all new vehicles in Morocco must comply with Euro 6b.[5]

South Africa

South Africa's first clean fuels programme was implemented in 2006 with the banning of lead from petrol and the reduction of sulphur levels in diesel from 3,000 parts per million (ppm) to 500ppm, along with a niche grade of 50 ppm.

The Clean Fuels 2 standard, expected to begin in 2017, includes the reduction of sulphur to 10 ppm; the lowering of benzene from 5 percent to 1 percent of volume; the reduction of aromatics from 50 percent to 35 percent of volume; and the specification of olefins at 18 percent of volume.

North America

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In Canada, the Canadian Environmental Protection Act, 1999 (CEPA 1999) transfers the legislative authority for regulating emissions from on-road vehicles and engines to Environment Canada from Transport Canada's Motor Vehicle Safety Act. The Regulations align emission standards with the U.S. federal standards and apply to light-duty vehicles (e.g., passenger cars), light-duty trucks (e.g., vans, pickup trucks, sport utility vehicles), heavy-duty vehicles (e.g., trucks and buses), heavy-duty engines and motorcycles.[6]


United States

Main article: United States vehicle emission standards

The United States has its own set of emissions standards that all new vehicles must meet. In the United States, emissions standards are managed by the Environmental Protection Agency (EPA). In 2014, the EPA published its "Tier 3" standards for cars, trucks and other motor vehicles, which tightened air pollution emission requirements and lowered the sulfur content in gasoline.[8]

EPA has separate regulations for small engines, such as groundskeeping equipment. The states must also promulgate miscellaneous emissions regulations in order to comply with the National Ambient Air Quality Standards.[9]

In December 2021 EPA issued new greenhouse gas standards for passenger cars and light trucks, effective for the 2023 vehicle model year.[10]

State-level standards

This section needs to be updated. Please help update this article to reflect recent events or newly available information. (December 2022)

Under federal law, the state of California is allowed to promulgate more stringent vehicle emissions standards (subject to EPA approval), and other states may choose to follow either the national or California standards. California had produced air quality standards prior to EPA, with severe air quality problems in the Los Angeles metropolitan area. LA is the country's second-largest city, by population, and relies much more heavily on automobiles and has less favorable meteorological conditions than the largest and third-largest cities (New York and Chicago).[11][12]

Some states have areas within the state that require emissions testing while other cities within the state do not require emission testing. Arizona emissions testing locations are located primarily in the two largest metropolitan areas (Phoenix and Tucson). People outside of these areas are not required to submit their vehicle for testing as these areas are the only ones that have failed the air quality tests by the state.

California's emissions standards are set by the California Air Resources Board (CARB). By mid-2009, 16 other states had adopted CARB rules;[13] given the size of the California market plus these other states, many manufacturers choose to build to the CARB standard when selling in all 50 states. CARB's policies have also influenced EU emissions standards.[citation needed]

California is attempting to regulate greenhouse gas emissions from automobiles, but faces a court challenge from the federal government. The states are also attempting to compel the federal EPA to regulate greenhouse gas emissions, which as of 2007 it has declined to do. On 19 May 2009, news reports indicate that the Federal EPA will largely adopt California's standards on greenhouse gas emissions.[14]

California and several other western states have passed bills requiring performance-based regulation of greenhouse gases from electricity generation.

In an effort to decrease emissions from heavy-duty diesel engines faster, CARB's Carl Moyer Program funds upgrades that are in advance of regulations.

The California ARB standard for light vehicle emissions is a regulation of equipment first, with verification of emissions second. The property owner of the vehicle is not permitted to modify, improve, or innovate solutions in order to pass a true emissions-only standard set for their vehicle driven on public highways. Therefore, California's attempt at regulation of emissions is a regulation of equipment, not of air quality. Vehicle owners are excluded from modifying their property in any way that has not been extensively researched and approved by CARB and still operate them on public highways. [neutrality is disputed]

South America



Main article: PROCONVE






Since 1 January 2022, all new vehicles in Cambodia must comply with Euro 4.[29]

From 1 January 2027, all new vehicles in Cambodia must comply with Euro 5.[29]


See also: Energy policy of China

Due to rapidly expanding wealth and prosperity, the number of coal power plants and cars on China's roads is rapidly growing, creating an ongoing pollution problem. China enacted its first emissions controls on automobiles in 2000, equivalent to Euro I standards. China's State Environmental Protection Administration (SEPA) upgraded emission controls again on 1 July 2004 to the Euro II standard.[30] More stringent emission standard, National Standard III, equivalent to Euro III standards, went into effect on 1 July 2007.[31] Plans were for Euro IV standards to take effect in 2010. Beijing introduced the Euro IV standard in advance on 1 January 2008, becoming the first city in mainland China to adopt this standard.[32]

Hong Kong

See also: Air pollution in Hong Kong

From 1 January 2006, all new passenger cars with spark-ignition engines in Hong Kong must meet either Euro IV petrol standard, Japanese Heisei 17 standard or US EPA Tier 2 Bin 5 standard. For new passenger cars with compression-ignition engines, they must meet US EPA Tier 2 Bin 5 standard.

The current standard is Euro 6C, it has been phased in since 2019.


Main article: Bharat stage emission standards

Bharat stage emission standards are emission standards instituted by the Government of India to regulate the output of air pollutants from internal combustion engine equipment, including motor vehicles. The standards and the timeline for implementation are set by the Central Pollution Control Board under the Ministry of Environment & Forests.

The standards, based on European regulations were first introduced in 2000. Progressively stringent norms have been rolled out since then. All new vehicles manufactured after the implementation of the norms have to be compliant with the regulations. By 2014, the country was under a combination of Euro 3 and Euro 4-based norms, with Euro 4 standards partly implemented in 13 major cities. Till April 2017, the entire country was under BS IV norms, which is based on Euro 4.[35]

As of now manufacturing and registration of BS VI vehicles has started, from April 2020 all BS VI manufacturing is mandatory, respectively.[35][36]



Starting 10 June 1968, the Japanese Government passed the Air Pollution Control Act [ja] which regulated all sources of air pollutants. As a result of the 1968 law, dispute resolutions were passed under the 1970 Air Pollution Dispute Resolution Act [ja]. As a result of the 1970 law, in 1973 the first installment of four sets of new emissions standards were introduced. Interim standards were introduced on 1 January 1975, and again for 1976. The final set of standards were introduced for 1978.[37] While the standards were introduced they were not made immediately mandatory, instead tax breaks were offered for cars which passed them.[38] The standards were based on those adopted by the original US Clean Air Act of 1970, but the test cycle included more slow city driving to correctly reflect the Japanese situation.[39] The 1978 limits for mean emissions during a "Hot Start Test" of CO, hydrocarbons, and NOx were 2.1 grams per kilometre (3.38 g/mi) of CO, 0.25 grams per kilometre (0.40 g/mi) of HC, and 0.25 grams per kilometre (0.40 g/mi) of NOx respectively.[39] Maximum limits are 2.7 grams per kilometre (4.35 g/mi) of CO, 0.39 grams per kilometre (0.63 g/mi) of HC, and 0.48 grams per kilometre (0.77 g/mi) of NOx. One interesting detail of the Japanese emissions standards was that they were introduced in a soft manner; that is, 1978 model year cars could be sold that did not meet the 1978 standards, but they would suffer various tax penalties. This gave manufacturers breathing room to properly engineer solutions and also incentivized fixing the best-selling models first, leading to smoother adoption of clean air standards and fewer drivability concerns than in many other markets.

The "10 - 15 Mode Hot Cycle" test, used to determine individual fuel economy ratings and emissions observed from the vehicle being tested, use a specific testing regime.[40][41][42]

In 1992, to cope with NOx pollution problems from existing vehicle fleets in highly populated metropolitan areas, the Ministry of the Environment adopted the Law Concerning Special Measures to Reduce the Total Amount of Nitrogen Oxides Emitted from Motor Vehicles in Specified Areas [ja], called in short The Motor Vehicle NOx Law. The regulation designated a total of 196 communities in the Tokyo, Saitama, Kanagawa, Osaka and Hyogo Prefectures as areas with significant air pollution due to nitrogen oxides emitted from motor vehicles. Under the Law, several measures had to be taken to control NOx from in-use vehicles, including enforcing emission standards for specified vehicle categories.

The regulation was amended in June 2001 to tighten the existing NOx requirements and to add PM control provisions. The amended rule is called the "Law Concerning Special Measures to Reduce the Total Amount of Nitrogen Oxides and Particulate Matter Emitted from Motor Vehicles in Specified Areas", or in short the Automotive NOx and PM Law.

Emission Standards

The NOx and PM Law introduces emission standards for specified categories of in-use highway vehicles including commercial goods (cargo) vehicles such as trucks and vans, buses, and special purpose motor vehicles, irrespective of the fuel type. The regulation also applies to diesel powered passenger cars (but not to gasoline cars).

In-use vehicles in the specified categories must meet 1997/98 emission standards for the respective new vehicle type (in the case of heavy duty engines NOx = 4.5 g/kWh, PM = 0.25 g/kWh). In other words, the 1997/98 new vehicle standards are retroactively applied to older vehicles already on the road. Vehicle owners have two methods to comply:

  1. Replace old vehicles with newer, cleaner models
  2. Retrofit old vehicles with approved NOx and PM control devices

Vehicles have a grace period, between 8 and 12 years from the initial registration, to comply. The grace period depends on the vehicle type, as follows:

Furthermore, the regulation allows fulfillment of its requirements to be postponed by an additional 0.5–2.5 years, depending on the age of the vehicle. This delay was introduced in part to harmonize the NOx and PM Law with the Tokyo diesel retrofit program.

The NOx and PM Law is enforced in connection with Japanese vehicle inspection program, where non-complying vehicles cannot undergo the inspection in the designated areas. This, in turn, may trigger an injunction on the vehicle operation under the Road Transport Vehicle Law.

Emission Regulations in Japan for vehicles

Table chart for Gasoline-fueled or LPG- fueled Motor Vehicles, Diesel-Powered Motor Vehicles, and Vehicle Fuel Efficiency Standards.[43]


From 1 January 2024, all new vehicles in Thailand must comply with Euro 5.[44]


Diesel and gasoline sulphur content is regulated at 10 ppm.[45] Turkey currently follows Euro VI for heavy duty commercial vehicles,[46] and, in 2016 a couple of years after the EU, Turkey adopted Euro 6 for new types of light duty vehicles (LDV) and new types of passenger cars.[47] Turkey is planning to use the worldwide harmonized light vehicles test procedure (WLTP).[48]

However, despite these tailpipe emission standards for new vehicle types there are many older diesel vehicles,[49] no low-emission zones and no national limit on PM2.5 particulates so local pollution, including from older vehicles, is still a major health risk in some cities, such as Ankara.[50][51] Concentrations of PM2.5 are 41 μg/m3 in Turkey, making it the country with the worst air pollution in Europe.[52] The regulation for testing of existing vehicle exhaust gases is Official Newspaper number 30004 published 11 March 2017.

An average of 135 g CO2/km for LDVs compared well with other countries in 2015,[53] however unlike the EU[54] there is no limit on carbon dioxide emissions.[55]


From 1 January 2022, all new cars in Vietnam must comply with Euro 5.[56]


Before the European Union began streamlining emissions standards, there were several different sets of rules. Members of the European Economic Community (EEC) had a unified set of rules, considerably laxer than those of the United States or Japan. These were tightened gradually, beginning on cars of over two liters displacement as the price increase would have less of an impact in this segment.[1] The ECE 15/05 norms (also known as the Luxemburg accord, strict enough to essentially require catalytic converters) began taking effect gradually: the initial step applied to cars of over 2000 cc in two stages, in October 1988 and October 1989.[2] There followed cars between 1.4 and 2.0 liters, in October 1991 and then October 1993. Cars of under 1400 cc had to meet two subsequent sets of regulations that applied in October 1992 and October 1994 respectively.[57] French and Italian car manufacturers, strongly represented in the small car category, had been lobbying heavily against these regulations throughout the 1980s.[58]

Within the EEC, Germany was a leader in regulating automobile emissions. Germany gave financial incentives to buyers of cars that met US or ECE standards, with lesser credits available to those that partially fulfilled the requirements. These incentives had a strong impact; only 6.5 percent of new cars registered in Germany in 1988 did not meet any emissions requirements and 67.3 percent were compliant with the strictest US or ECE standards.[1]

Sweden was one of the first countries to instill stricter rules (for 1975), placing severe limitations on the number of vehicles available there. These standards also caused drivability problems and steeply increased fuel consumption - in part because manufacturers could not justify the expenditure to meet specific regulations that applied only in one very small market. In 1982, the European Community calculated that the Swedish standards increased fuel consumption by 9 percent, while it made cars 2.5 percent more expensive.[59] For 1983 Switzerland (and then Australia) joined in the same set of regulations, which gradually increased the number of certified engines.[60] One problem with the strict standards was that they did not account for catalyzed engines, meaning that vehicles thus equipped had to have the catalytic converters removed before they could be legally registered.

In 1985 the first catalyzed cars entered certain European markets such as Germany. At first, the availability of unleaded petrol was limited and sales were small. In Sweden, catalyzed vehicles became allowed in 1987, benefitting from a tax rebate to boost sales.[61] By 1989 the Swiss/Swedish emissions rules were tightened to the point that non-catalyzed cars were no longer able to be sold. In early 1989 the BMW Z1 was introduced, only available with catalyzed engines. This was a problem in some places like Portugal, where unleaded fuel was still almost non-existent, although European standards required unleaded gasoline to be "available" in every country by 1 October 1989.[62]

European Union

Main article: European emission standards

The main source of greenhouse gas emissions in the European Union is transportation. In 2019, it contributes to about 31% of global emissions and 24% of emissions in the EU. In addition, up to the COVID-19 pandemic, emissions have only increased in the transport economic sector.[63][64] In 2019, about 95% of the fuel came from fossil sources.[65]

The European Union has its own set of emissions standards that all new vehicles must meet. Currently, standards are set for all road vehicles, trains, barges and 'nonroad mobile machinery' (such as tractors). No standards apply to seagoing ships or airplanes.

EU Regulation No 443/2009 set an average CO2 emissions target for new passenger cars of 130 grams per kilometre. The target was gradually phased in between 2012 and 2015. A target of 95 grams per kilometre applies from 2021.

For light commercial vehicle, an emissions target of 175 g/km applies from 2017, and 147 g/km from 2020,[66] a reduction of 16%.

The EU introduced Euro 4 effective 1 January 2008, Euro 5 effective 1 January 2010, and Euro 6 effective 1 January 2014. These dates had been postponed for two years to give oil refineries the opportunity to modernize their plants.

From January 2022, all new light vehicles must comply with Euro 6d. From 1 January 2023, all new motorcycles must comply with Euro 5.


According to the German federal automotive office 37.3% (15.4 million) cars in Germany (total car population 41.3 million) conform to the Euro 4 standard from Jan 2009.



This article needs to be updated. Please help update this article to reflect recent events or newly available information. (September 2020)

Several local authorities in the UK have introduced Euro 4 or Euro 5 emissions standards for taxis and licensed private hire vehicles to operate in their area.[68][69][70] Emissions tests on diesel cars have not been carried out during MOTs in Northern Ireland for 12 years, despite being legally required.[71]

From January 2022, all new light vehicles must comply with Euro 6d.[72] From 1 January 2023, all new motorcycles must comply with Euro 5.[73]



Australian noxious emission standards are based on European regulations for light-duty and heavy-duty (heavy goods) vehicles, with acceptance of selected US and Japanese standards. The current policy is to fully harmonize Australian regulations with United Nations (UN) and Economic Commission for Europe (ECE) standards. In November 2013, the first stage of the stringent Euro 5 emission standards for light vehicles was introduced, which includes cars and light commercial vehicles.[74] The development of emission standards for highway vehicles and engines is coordinated by the National Transport Commission (NTC) and the regulations—Australian Design Rules (ADR)—are administered by the Department of Infrastructure and Transport.[75][76]

All new vehicles manufactured or sold in the country must comply with the standards, which are tested by running the vehicle or engine in a standardized test cycle.[77]

In April 2023, the Australian government released its National Electric Vehicle Strategy, which included a commitment to introduce a Fuel Efficiency Standard to address greenhouse gas emissions.[78] The government undertook consultation on the model for the standard in April and May 2023, and they intend to introduce legislation by the end of 2023[79] Research commissioned by environmental NGO Solar Citizens has calculated that a Fuel Efficiency Standard that started at 95g CO2/km and reduced to 0g CO2/km over ten years would save Australian motorists $11b over the first five years.[80]

From December 2025, all new vehicles sold in Australia will have to comply with Euro 6d.[81]

See also


  1. ^ a b c Dicorato, Giuseppe (January 1989). "Entriamo in Zona Verde" [Entering the Green Zone]. Quattroruote (in Italian). Vol. 34, no. 399. Milan, Italy: Editoriale Domus. p. 151.
  2. ^ a b c Dicorato, p. 152
  3. ^ "Smog Check – Vehicle Emissions Tests" (PDF). Emissions.org. Archived from the original (PDF) on November 20, 2008.
  4. ^ "West African Ministers adopt cleaner fuels and vehicles standards". UNEP. 27 February 2020.
  5. ^ "Norme antipollution. Le Maroc passe officiellement au carburant Euro 6 dès 2022". Challenge.ma.
  6. ^ "Vehicle and Engine Regulations". Environment Canada. Jul 17, 2013.
  7. ^ a b "Semarnat publica en el DOF modificación a la NOM-044". t21.com.mx.
  8. ^ U.S. Envrionmental Protection Agency (EPA), Washington, D.C. (2014-04-18). "Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards." Final rule. Federal Register, 79 FR 23414
  9. ^ "EPA Emission Standards for Nonroad Engines and Vehicles". EPA. 2022-09-13.
  10. ^ "EPA Finalizes Greenhouse Gas Standards for Passenger Vehicles, Paving Way for a Zero-Emissions Future". EPA. 2021-12-20. News Release.
  11. ^ "City and Town Population Totals: 2020-2021". Census.gov. Retrieved 2023-05-02.
  12. ^ Littman, Fred E.; Magill, P. L. (2012). "Some Unique Aspects of Air Pollution in Los Angeles". Air Repair. 3 (1): 29–34. doi:10.1080/00966665.1953.10467586. ISSN 0096-6665.
  13. ^ "How the California Air Resources Board (CARB) Works". howstuffworks.com. 12 September 2008. Retrieved 4 April 2018.
  14. ^ Simon, Richard (2009-05-19). "U.S. to limit greenhouse gas emissions from autos". Los Angeles Times.
  15. ^ Panzera, Daniel (September 1, 2015). "En el 2016 entrará en vigor la norma Euro V para camiones y transporte de pasajeros". 16 Valvulas.
  16. ^ "DPF: la sigla que se convirtió en un dolor de cabeza para automotrices y usuarios argentinos". Motor1.com.
  17. ^ "Indústria pronta para Euro 5 em 2012 - Diário do Grande ABC - Notícias e informações do Grande ABC: economia". Dgabc.com.br. 26 March 2011.
  18. ^ "Programa de Controle da Poluição do Ar por Veículos Automotores" (PDF). Ibama.gov.br. Retrieved 26 July 2022.
  19. ^ "Nova lei de emissões vai tirar de linha 6 carros e 4 motores até o fim do ano; veja lista". Autoesporte.globo.com. 3 December 2021.
  20. ^ "Novos limites de emissões vão aquecer venda de implementos rodoviários". Estradao.estadao.com.br. 11 February 2022.
  22. ^ O, Catalina Rojas (4 February 2013). "Euro 5: la norma de emisiones para vehículos que empieza este año y que posiciona a Chile como líder en Latinoamérica". La Tercera.
  23. ^ "Chile avanza hacia la norma de emisiones Euro 6b". Autocosmos. 2 October 2020.
  24. ^ "ANAC aclara que norma de emisiones Euro 6c comenzará a regir desde el 30 de septiembre de 2025 – Anac".
  25. ^ "¿El transporte en Colombia está listo para la Euro VI?". Semana.com Últimas Noticias de Colombia y el Mundo. 16 March 2022.
  26. ^ "Ley 1972 de 2019".
  27. ^ "Peru adopts Euro 4 / IV vehicle emissions standards for improved air quality". UN Environment. December 18, 2017.
  28. ^ "Decreto Supremo que modifica el Decreto Supremo N° 010-2017-MINAM, que establece Límites Máximos Permisibles de emisiones atmosféricas para vehículos automotores" [Maximum permissible limits of atmospheric emissions for motor vehicles] (in Spanish). Peru. 2021. 2021-MINAM. Retrieved 2023-12-18.
  29. ^ a b "Cambodia In The Driver's Seat Toward Euro VI Standards | Climate & Clean Air Coalition". www.ccacoalition.org.
  30. ^ "China to adopt auto emission standard equal to Euro III in 2008". Chinadaily.com.cn. 2004-07-07. Retrieved 2011-02-02.
  31. ^ "China Launches Tougher Auto Emission Standard". English.cri.cn. Archived from the original on November 14, 2007. Retrieved 2011-02-02.
  32. ^ "China: Beijing launches Euro 4 standards". Automotiveworld.com. 2008-01-04. Retrieved 2011-02-02.
  34. ^ a b "Emission Standards: China: Cars and Light Trucks". dieselnet.com.
  35. ^ a b Lathia, Rutvik; Dadhaniya, Sujal (2019-01-20). "Policy norms and proposed ways to achieve goals of Indian vehicle emission program". Journal of Cleaner Production. 208: 1339–1346. doi:10.1016/j.jclepro.2018.10.202. ISSN 0959-6526. S2CID 158500168.
  36. ^ Nishant Parekh (August 30, 2019). "Clearing the air on BS6". Autocarindia.com.
  37. ^ Yamaguchi, Jack K. (1979), Lösch, Annamaria (ed.), "The Year of Uncertainty?", World Cars 1979, Pelham, NY: The Automobile Club of Italy/Herald Books: 61–62, ISBN 0-910714-11-8
  38. ^ Yamaguchi, Jack K. (1977), "The Year of the Third Power", World Cars 1977, Pelham, NY: The Automobile Club of Italy/Herald Books: 54, ISBN 0-910714-09-6
  39. ^ a b Yamaguchi, Jack K. (1978), Lösch, Annamaria (ed.), "Successes- Excesses", World Cars 1978, Pelham, NY: The Automobile Club of Italy/Herald Books: 61, ISBN 0-910714-10-X
  40. ^ "Japanese gasoline emission limits" (PDF). Walshcarlines.com. p. 28. Retrieved 2022-07-27.
  41. ^ "Emission Test Cycles: Japanese 10-15 Mode". Dieselnet.com. Retrieved 4 April 2018.
  42. ^ "Fuel economy label generator". Fuel economy label generator. Retrieved 4 April 2018.
  43. ^ "Emission Regulation in Japan for vehicles – Japan Inspection Organization". Retrieved 2024-01-03.
  44. ^ "Thailand approves delay on imposing Euro 5 emission standard on new vehicles". Pattaya Mail. 22 February 2023.
  45. ^ "Country Name Turkey" (PDF). Wedocs.unep.org. Retrieved 7 February 2019.
  46. ^ "Left in the dust: Brazil might be the last major automotive market to adopt Euro VI standards". International Council on Clean Transportation. 23 May 2018.
  48. ^ "New WLTP emissions test: when it's in force and how it could affect your car". Autocar.co.uk. 17 April 2018.
  49. ^ "Diesel cars increase by 116% in last 5 years in Turkey". Anadolu Agency. 10 February 2017.
  50. ^ "Only six Turkish cities have clean air, report says". Ahval. 7 January 2018.
  51. ^ "Air Pollution and Health in Turkey" (PDF). Health and Environment Alliance (HEAL). Retrieved 6 February 2019.
  52. ^ "Mapped: Europe's Most and Least Polluted Countries". Greenmatch.co.uk. Retrieved 6 February 2019.
  53. ^ "International comparison of light-duty vehicle fuel economy: Turkey" (PDF). Globalfueleconomy.org. Retrieved 7 February 2019.
  54. ^ "CO2 emission standards for cars and vans: Council confirms agreement on stricter limits". European Council. Retrieved 7 February 2019.
  55. ^ "Reducing vehicle emissions in Turkey". International Council on Clean Transportation. Retrieved 6 February 2019.
  56. ^ "Euro 5 emission standards to be rolled out for new cars in Vietnam early 2022 | Environment | Vietnam". En.vietnamplus.vn. December 10, 2021.
  57. ^ Dicorato, p. 154
  58. ^ "Das schadstoffarme Auto: Fragen und Antworten" [The clean car: Questions and Answers]. Die Welt (in German) (91): 5. 1985-04-19.
  59. ^ Isakson, Börje, ed. (1982-10-06). "Avgaskrav slukar bensin" [Emissions requirements devour petrol]. Teknikens Värld (in Swedish). Vol. 34, no. 21. Stockholm, Sweden: Specialtidningsförlaget AB. p. 54.
  60. ^ Hogsten, Dag E. (1982-10-06). "Alfa med ny spänst" [Alfa with new vitality]. Teknikens Värld (in Swedish). Vol. 34, no. 21. Stockholm, Sweden: Specialtidningsförlaget AB. p. 44.
  61. ^ Krav på katalysatorrening för alla bilar i trafik [Demand for catalyzing all vehicles in traffic] (Motion 1997/98:Jo714) (in Swedish). Riksdag [Swedish Parliament]. 29 September 1997.
  62. ^ Dicorato, p. 155
  63. ^ "Get on the bus first to make Nicosia tram infrastructure worth the investment". European Investment Bank. Retrieved 2022-09-01.
  64. ^ "Transport emissions". ec.europa.eu. Retrieved 2022-09-01.
  65. ^ Le Quéré, Corinne; Jackson, Robert B.; Jones, Matthew W.; Smith, Adam J. P.; Abernethy, Sam; Andrew, Robbie M.; De-Gol, Anthony J.; Willis, David R.; Shan, Yuli; Canadell, Josep G.; Friedlingstein, Pierre; Creutzig, Felix; Peters, Glen P. (July 2020). "Temporary reduction in daily global CO2 emissions during the COVID-19 forced confinement". Nature Climate Change. 10 (7): 647–653. Bibcode:2020NatCC..10..647L. doi:10.1038/s41558-020-0797-x. hdl:10871/122774. ISSN 1758-6798. S2CID 218693901.
  66. ^ International Council on Clean Transportation (January 2014). "EU CO2 standards for passenger cars and light-commercial vehicles". Retrieved 5 February 2014.
  67. ^ a b "Emission Standards: Russia and EAEU". dieselnet.com.
  68. ^ "Taxi emissions ruling set for January start". Woking News & Mail. 18 October 2013. Retrieved 17 December 2013.
  69. ^ "Chichester District Council: European emission standard EURO 4". Chichester District Council. Archived from the original on 2013-12-17. Retrieved 2013-12-13.
  70. ^ "European technology emission standards: how to check your vehicle" (PDF). Plymouth City Council. Archived from the original (PDF) on 2013-12-17. Retrieved 2013-12-13.
  71. ^ "MOT diesel test not performed in NI for 12 years". BBC Northern Ireland News. 26 September 2018. Retrieved 26 September 2018.
  72. ^ "Full guide to Euro 6 for vans and pickups, including Euro 6d and Euro VI". Parkers.
  73. ^ "What Euro 5 Means for UK Motorcycles | Honda Engine Room". www.honda.co.uk.
  74. ^ Services, Department of Transport and Regional. "Vehicle Emission Standards". Infrastructure.gov.au. Retrieved 2016-11-11.
  75. ^ "Emission Standards: Australia: On-Road Vehicles and Engines". Dieselnet.com. Retrieved 2016-11-11.
  76. ^ "Vehicle emission standards". Department of Infrastructure, Transport, Regional Development and Communications, Australian Government. 2021-11-15. Retrieved 2022-02-18.
  77. ^ Mortimore, Anna. "Australia's weaker emissions standards allow car makers to 'dump' polluting cars". The Conversation. Retrieved 2016-11-11.
  78. ^ Australia. Dept of Climate Change, Energy, the Environment and Water (19 April 2023). "The National Electric Vehicle Strategy". The National Electric Vehicle Strategy. Retrieved 29 August 2023.((cite web)): CS1 maint: multiple names: authors list (link)
  79. ^ Costello, Mike (2023-04-19). "Government plans fuel efficiency standards to improve EV supply". CarExpert. Retrieved 2023-08-29.
  80. ^ "Recharging Australia : how to save Australia $11 billion in fuel costs and electrify our fleet". Solar Citizens. 1 March 2023. Retrieved 29 August 2023.
  81. ^ "Strict new-car emissions standards coming to Australia from 2025, utes and 4WDs among hardest hit". Drive. December 22, 2023.