
Stage IIIA was phased in:
- between 2010 and 2012 for constant speed engines,
- between 2005 and 2009 for propulsion engines for inland waterway vessels,
- between 2005 and 2009 for railcars and locomotives, and
- between 2005 and 2008 for other engines.
Stage IIIB was then introduced between 2011 and 2013 for land-based application engines between 37 and 560 kW, in 2011 for locomotive and railcar engines above 130 kW.
The emissions legislation on non-road mobile machinery (NRMM) covers a huge range of applications. For simplicity, small (less than 19 kW) engines are covered in a specific page on small equipment but the larger applications are covered on this page.
For the small engines (less than 19 kW) many are petrol engines, but for the larger engines the majority are diesels.
The emissions requirements for NRMM appear quite complex as they come into force in stages, with each stage phased depending on the application and the engine size.
Within each of these applications there are distinct application dates for different engine sizes, with the date for all engines placed on the market generally being one year after the date for new Type Approvals.
Stage IV was phased in between 2013 and 2014, only for land-based application engines between 56 and 560 kW.
Stage V will be introduced on 1 January 2018 for engine type-approval and on 1 January 2019 for placing on the market of engines; except for land-based (NRE) engines between 56 and 130 kW which benefit from a one-year delay and rail engines, both for railcars and locomotives, which benefit from a two-year delay.

The systems used are the same as for other heavy-duty diesel vehicles, with Diesel Particulate Filters (DPF), Diesel Oxidation Catalysts (DOC) and Selective Catalytic Reduction (SCR) as the main technologies. They can be used as original equipment or are available as retrofit systems for most equipment.
In addition to Europe-wide legislation, there are sometimes local regulations for construction equipment (as in Switzerland) or for equipment used in mines. There may also be incentives, requirements built into construction contracts (especially in city centres) or company internal policies that stimulate the use of these technologies. Diesel Particulate Filters, for instance, can be used for heavy-duty forklift trucks, where the power of a diesel engine is needed for the loads but operation within buildings is needed.

Diesel Particulate filters also show their benefit on equipment used in confined construction sites, where the need for heavy construction equipment can at the same time meet the needs of public protection from exposure to fine particles.
Supply of the urea for NOx removal by Selective Catalytic Reduction is quite straightforward in such circumstances as a single supply can be set up for all equipment on site. The use of SCR technology on NRMM has largely developed since the introduction of Stage IIIB requirements, often offering machinery operators some benefits on fuel consumption and CO2 emissions reduction. SCR is also increasingly being applied to Inland Waterway vessels, such as those used on the Rhine and to ships and ferries for international use, which are not covered by the NRMM regulations, but by the International Maritime Organization (IMO).

Recreational craft and personal watercraft
Emissions regulations also exist for ‘recreational and personal watercraft’ – in other words boats and equipment such as jet-skis. The requirements cover boats for leisure use or sports (but not racing boats) with a hull length from 2.5 m to 24 m and personal watercraft up to 4 m in length. Inboard, outboard and stern-drive engines and equipment using water jet pumps for propulsion are all covered. The first stage of European regulations was introduced in 2005 and a Stage II is introduced in January 2017. They do not generally require exhaust emissions aftertreatment, but it is used in the USA for numerous applications.

Tractors
The NRMM emissions Directive do not directly apply to agricultural and forestry tractors, but a parallel Regulation sets essentially the same series of requirements as for NRMM, again phased in by engine size.