Low-emission Zone

Retrofitting / Tax relief / Financing

Older diesel vehicles that are not awarded a green sticker may not enter the low-emission zone. However, it is not always necessary to replace vehicles since they can often be retrofitted with a particulate filter. This applies in particular to vehicles with a yellow sticker.

Filter retrofitting – what is it good for?

Equipping a diesel filter with a particulate filter is an active contribution to protecting health and the climate because, depending on their design, particulate filters can remove more than 90 % of particles from diesel emissions. Filters with such a high level of efficiency are used to retrofit trucks. The level of efficiency for filters for cars is generally between 30 and 60 % as simpler designs are used.

Particulate filters can also filter out the tiniest of particles, not because they get caught in the holes like with a sieve but because they are deposited on the inner surfaces of the filter material as a result of diffusion and inertia effects. What is difficult with a particulate filter is not retaining the particles in the filter but the removal of the soot particles that accumulate in the filter in order to prevent it from clogging up. The soot particles must be incinerated for the purpose of regeneration. To this end, the exhaust gas and the filter must become hot enough for the soot to ignite. The process is facilitated by catalytic surfaces or by additives and nitrogen dioxide in the exhaust gas.

Particulate filter retrofitting

Most diesel vehicles can be retrofitted with particulate filters.
Retrofitted vehicles are reclassified into a better emission group and are more likely to be permitted to drive in low-emission zones. Emission group reclassification is determined by Marking Ordinance (35th Ordinance for the implementation of the Federal Immission Protection Act).
You can find further information on this under: Sticker

Only certified filters may be used for retrofitting. The technical requirements for particulate filters are specified in Annexe XXVI (Cars/light commercial vehicles) and Annexe XXVII (Trucks) of the German Road Traffic Licensing Regulations (StVZO). The systems are tested in prescribed driving cycles and must, for example, meet a specific level of retention and ensure a certain service life. They are then given a general operating permit by the Federal Motor Transport Authority.

The filters are assigned to the particle-reduction classes PM 01 to PM 4 (for cars) and PMK 01 to PMK 4 (for trucks) depending on the particle reduction achieved.

The particle reduction level determines the emission group (sticker) that is achieved after retrofitting. You can find information on the assignment of your vehicle to an emission class under Sticker

The workshop will issue a certificate concerning the installation of the filter system. The licensing office will make an entry in section 22 of the vehicle documents based on this certificate and may award a higher category sticker.

Where can I find information about retrofitting for my vehicle on the Internet?

You can find information on retrofitting options in this Internet database
It may be worthwhile consulting several workshops or even a repair shop specialising in retrofitting. Vendors and manufacturers of retrofit systems will also be able to provide information, for example via the Internet.

Emissions standard classification and road tax

A vehicle's emissions standard classification (Euro norm) and its corresponding classification for German road tax will not change as a result of a filter being fitted since it does not reduce the other restricted pollutants.

Is there a funding for particulate filter retrofitting?

In 2016 particulate filter retrofitting of passenger cars and light duty vehicles is funded with 260 € by the Federal Government funding programme.

The Federal Office of Economics and Export Control (BAFA) is responsible for managing such a programme. You can get more details from its website at Federal Office of Economics and Export Control (BAFA).

What bonus programmes or financial possibilities exist for commercial vehicles?

There are various programmes at federal and state level to support company investments. The information below is by no means exhaustive. The listed requirements are also subject to change, and we cannot accept any liability for the accuracy of the information. It is always advisable to make direct contact with the organisation concerned.

KfW Banking Group

The KfW environmental programmes (programme numbers 240, 241) support the purchase of low-emission and low-noise commercial vehicles that meet the Euro 6 exhaust emission standard with low-interest loans.
Support is also provided for the purchase of bio-methane- or natural gas-powered vehicles that meet the Euro 6 exhaust emission standard or, in the case of heavy goods vehicles, at least the EEV standard, as well as for the establishment of filling stations for these fuels.
The KfW Mittelstandsbank (SME bank) information center can be reached under service number 01801/241124 and will advise on the programmes that KfW Mittelstandsbank offers. Commercial environmental protection is also provided for. Advisory staff of KfW Förderbank (development bank) can be reached under service number 01801/335577 between 7.30 am and 6.30 pm, Monday to Friday.
You can find further information on this under:

Investment Bank Berlin

The Investment Bank Berlin (IBB) also provides support to Berlin-based small and medium-sized enterprises for environmentally compatible retrofitting or for the purchase of new commercial vehicles. It provides various credit programmes. IBB employees are available to answer your email questions under and via the hotline number ++49 30 / 2125-4747.

Assistance for vehicles using natural gas

Natural gas is an especially clean fuel, which is why there is a reduced fuel tax rate for natural gas until 2018. This means that natural gas is a very cost-efficient fuel. In comparison with petrol, fuel costs can be around 50 % and in comparison with diesel around 30 % lower. The additional costs for natural gas-powered can therefore be covered by lower fuel costs.

In Berlin there are already 23 fuelling stations for compressed natural gas. There location can be found for example on the website of the Berlin natural gas provider GASAG on

General information on natural gas vehicles: