The full title of the Marking Regulations is "35th Regulations implementing the Federal Immission Control Act of 10 October 2006 (Regulations on the Marking of Low-Polluting Motor Vehicles)". The first amending regulations entered into force on 8 December 2007.

The regulations govern the marking of passenger cars and commercial vehicles to identify their pollutant emission category by means of a sticker affixed to the inside of their windscreen, as well as exemptions from the marking requirement.

The Marking Regulations do not themselves establish any low emission zones or driving restrictions. This can be done by the competent local authorities if the air quality limit values are exceeded, traffic is a relevant cause and the establishment of a low emission zone is included as a measure in the local authority's air quality action plan.

The stickers are issued by the registration authorities and by the bodies authorized to conduct emissions testing, such as automotive repair shops, TÜV, DEKRA or other technical inspection organizations. Tourists or keepers of vehicles registered abroad can also obtain the required sticker from the above-mentioned agencies. If these recognized bodies operate bases in other countries and provide this service, the stickers for vehicles registered abroad can also be obtained there.

The price of the stickers is not governed by the Marking Regulations. It may therefore vary from region to region. It is usually between 5 and 10 euros. If the stickers are mailed, higher fees, including postage, may be payable. The stickers are valid for all low emission zones throughout Germany, not only in the municipality in which they were issued. However, the driving restrictions imposed by local authorities may vary, depending on the level of pollution. For more detailed information, please contact your local authority.

The Marking Regulations define four different pollutant emission categories, which apply to both passenger cars and commercial vehicles (HGVs, buses, semi-trailer towing vehicles, etc.).

The four pollutant emission categories are based on the exhaust emission standards for diesel vehicles (Euro 1 to Euro 4 for passenger cars and Euro I to Euro V and EEV for commercial vehicles). Vehicles meeting a more stringent exhaust emission standard, such as Euro 5 for passenger cars, are placed in the best pollution emission category. This is pollutant emission category 4.

Diesel vehicles retrofitted with particulate abatement equipment, such as particulate traps, generally qualify for the next higher pollutant emission category. The category for which a vehicle qualifies as a result of retrofitting is called "particulate abatement level" (PM) in the case of passenger cars and "particulate abatement category" (PMK) in the case of commercial vehicles (HGVs, buses, semi-trailer towing vehicles, etc.).

There are only two categories for passenger cars and commercial vehicles with positive-ignition engines (petrol vehicles):

• pollutant emission category 1 for passenger cars and commercial vehicles that do not meet the standards of category 4. Stickers are not issued for this category.
• pollutant emission category 4 for all passenger cars and commercial vehicles that meet the Euro 1 to Euro 4 requirements.

Pollutant emission category 4 also applies to all motor vehicles with positive-ignition engines that meet at least the requirements of Annex XXIII to the German Road Traffic Registration Regulations (emission code number 01 or 02) or of the 52nd Exemption Regulations on the German Road Traffic Registration Regulations (emission code number 77), and to motor vehicles with positive-ignition engines that meet future requirements, such as Euro 5 or Euro 6.

Simplified overview of the sticker requirements (as at 31 December 2010)

Pollutant emission	1	2	3	4
	No Sticker	Red Sticker	Yellow Sticker	Green Sticker
Requirements for diesel cars (compression ignition)	Euro 1 or more polluting	Euro 2 or Euro 1 with particulate trap	Euro 3 or Euro 2 with particulate trap	Euro 4 or Euro 3 with particulate trap or more stringent emission standards
Requirements for petrol cars or commercial vehicles (positive ignition)	More polluting than pollutant emission category 4	Not issued	Not issued	Annex XXIII to the German Road Traffic Registration Regulations, exhaust gas cleaning system in accordance with the 52nd Exemption Regulations to the German Road Traffic Registration Regulations, Euro 1 to Euro 4 or Euro I (S 1) to Euro V (S 5) and EEV and more stringent emission standards
Requirements for diesel commercial vehicles (compression ignition)	Euro I (S 1) or more polluting	Euro II (S 2) or Euro I (S 1) with particulate trap	Euro III (S 3) or Euro II (S 2) with particulate trap	Euro IV (S 4), Euro V (S 5), EEV or Euro III (S 3) with particulate trap and more stringent emission standards

In order to find out the pollutant emission category into which your vehicle falls, you normally require the emission code number recorded in your vehicle’s registration documents. If your vehicle has been retrofitted with particulate abatement equipment, the new "particulate abatement level" (PM) for passenger cars or "particulate abatement category" (PMK) for commercial vehicles certified by the automotive repair shop has to be added (under item 22 of the new vehicle registration documents) by the registration authority. Only after this entry has been made in your vehicle documents will you be able to obtain a higher category sticker than the one that would have been issued on the basis of your vehicle’s emission code number. This means that retrofitting a vehicle does not change its emission code number.

In vehicle documents issued before 1 October 2005, the 5th and 6th digit of the 6-digit code in the box "Schlüsselnummern zu 1" (code numbers re 1) in the vehicle registration document represent the emission code number.

In vehicle documents issued after 1 October 2005, the emission code number can be found in box 14.1 of Part I of the registration certificate. It is the last two numbers in the sequence of digits. The first two numbers in the sequence of digits indicate whether the vehicle is a passenger car (04) or a commercial vehicle (06).

Emission code numbers for passenger cars and commercial vehicles which are used to classify vehicles in the relevant pollutant emission category in accordance with Section 2(2) and Annex 2 of the 35th Federal Immission Control Regulations

1. Motor vehicles powered by petrol, natural gas or ethanol (positive-ignition engine)

Pollutant emission category / sticker	Pollutant emission category 2	Pollutant emission category 3	Pollutant emission category 4
Passenger cars			01, 02, 14, 16, 18 to 70 - 71 to 75 - *) 77
Commercial vehicles			30 to 55, 60, 61 - 70, 71, 80, 81, 83, 84, 90, 91 -  *)

*) In the case of gas fuelled vehicles in accordance with Directive 2005/55/EC (previously Directive 88/77/EEC)

2. Diesel and biodiesel powered vehicles (compression-ignition engine) not retrofitted with particulate abatement equipment

Pollutant emission category / sticker	Pollutant emission category 2	Pollutant emission category 3	Pollutant emission category 4
Passenger cars	25 to 29, 35, 41, 71	30, 31, 36, 37, 42, 44 to 52, 72	32, 33, 38, 39, 43, 53 to 70, 73 to 75 or level PM 5
Commercial vehicles	20, 21, 22, 33, 43, 53, 60, 61	34, 44, 54, 70, 71	35, 45, 55, 80, 81, 83, 84, 90, 91

3. Diesel and biodiesel powered vehicles (compression-ignition engine) retrofitted with particulate abatement equipment

Pollutant emission category / sticker	Pollutant emission category 2	Pollutant emission category 3	Pollutant emission category 4
Passengers cars retrofitted to meet the requirements for	Particulate abatement level PM 01: 19, 20, 23, 24 Particulate abatement level PM 0: 14, 16, 18, 21, 22, 34, 40, 77	Particulate abatement level PM 0: 28, 29 Particulate abatement level PM 1: 14, 16, 18, 21, 22, 25 bis 27, 34, 35, 40, 41, 71, 77	Particulate abatement level PM 1: 27 +), 49 bis 52 Particulate abatement level PM 2: 30, 31, 36, 37, 42, 44 bis 48, 67 bis 70 Particulate abatement level PM 3: 32, 33, 38, 39, 43, 53 bis 66 Particulate abatement level PM 4: 44 bis 70
Commercial vehicles retrofitted to meet the requirements for	Particulate abatement level PM 01: 40-42, 50-52 Particulate abatement level PM 0: 10-12, 30-32. 40-42. 50-52	Particulate abatement level PM 0: 43, 53 Particulate abatement level PM 1: 10-12, 20-22, 30-33, 40-43, 50-53, 60, 61	Particulate abatement category PMK 1: 44, 54 Particulate abatement category PMK 2: 10-12, 20-22, 30-34, 40-45, 50-55, 60, 61, 70, 71 Particulate abatement category PMK 3: 33-35, 44, 45, 54, 55, 60, 61, Particulate abatement category PMK 4: 33-35, 44, 45, 54, 55, 60, 61

+) Passenger cars with emission code numbers "27" or "0427" and the plaintext “96/69/EC I” with a maximum authorized mass of over 2,500 kilograms will be issued a green sticker pursuant to paragraph 1(4)(n) of Annex 2 to the Marking Regulations if it is demonstrated that the car meets the requirement of level PM 1 in Annex XXVI to the German Road Traffic Registration Regulations.

All other passenger cars with emission code numbers "27" or "0427" meeting the requirements of level PM 1 may only be issued a yellow sticker. This generally applies to passenger cars having more than 6 seats and a maximum authorized mass of up to 2,500 kilograms.

The low emission zones are identified by traffic signs 270.1 and 270.2 of the German Road Traffic Regulations. The supplementary sign specifies which stickers vehicles need to display in order to enter the individual low emission zone.

Vehicles not displaying a sticker may not enter a low emission zone; offenders face a fine of 80 euros. This applies even if the vehicle is eligible for a sticker due to its emission code number. Vehicles registered in another country also require a sticker.

Annex 3 to the Marking Regulation contains block exemptions from compulsory marking. For instance, two- and three-wheeled vehicles are exempt, as are ambulances and vintage cars with a so-called "H registration". In addition, this prohibition does not apply to motor vehicles for the carriage of disabled persons with severe walking difficulties, bilateral amelia and phocomelia or with comparable functional impairments as well as blind persons. In addition, local authorities may permit exemptions on a case-by-case basis. In this case, a request has to be submitted. You should contact your local authority for more details. In some federal states, such exemptions are also recognized in other low emission zones. However, the federal states have not given their consent to the Federal Government's suggestion that all exemptions be mutually recognized.

Petrol-engined cars (which are generally equipped with a catalytic converter) registered in accordance with Annex XXIII to the German Road Traffic Registration Regulations, the so-called US standard, or retrofitted in accordance with the 52nd  Exemption Regulations to the German Road Traffic Registration Regulations will also be issued a green sticker.  This covers passenger cars with emission code numbers 01, 02 and 77. They are thus allowed to enter the low emission zone.

In addition, vintage vehicles (in accordance with Section 2(22) of the Vehicle Licensing Regulations) carrying a number plate as described in Section 9(1) or Section 17 of the Vehicle Licensing Regulations (so-called "H registration") are normally exempt from the traffic prohibitions in low emission zones.

There are no financial incentives in 2014 for retrofitting a diesel vehicle with a particulate trap. No decision has yet been taken as to whether financial assistance will be provided in the years ahead.