* Il [[commercio internazionale delle emissioni]] stabilito dall'articolo 17.
IET is relevant as the reductions achieved through CDM projects are a compliance tool for EU ETS operators. These Certified Emission Reductions (CERs) can be obtained by implementing emission reduction projects in developing countries, outside the EU, that have ratified (or acceded to) the Kyoto Protocol. The implementation of Clean Development Projects is largely specified by the [[Marrakech Accords]], a follow-on set of agreements by the Conference of the Parties to the [[Kyoto Protocol]].
The legislators of the EU ETS drew up the scheme independently but called on the experiences gained during the running of the voluntary [[ UK Emissions Trading Scheme]] in the previous years,<ref>[http://www.decc.gov.uk/en/content/cms/what_we_do/change_energy/tackling_clima/ccas/uk_ets/uk_ets.aspx UK Emissions Trading Scheme] DECC</ref> and collaborated with other parties to ensure its units and mechanisms were compatible with the design agreed through the UNFCCC.
Under the EU ETS, the governments of the EU Member States agree on '''national emission caps''' which have to be approved by the EU commission. Those countries then allocate allowances to their industrial operators, and track and validate the actual emissions in accordance with the relevant assigned amount. They require the allowances to be retired after the end of each year.