The United Nations Environment Programme (UNEP) is the leading global authority on the environment. UNEP supports governments at all levels to detect and reduce harmful and high emitting pollutants from key sectors such as agriculture, waste, fossil fuels, household energy, vehicles and cooling. In the transportation sector, UNEP has made significant strides through its Partnership for Clean Fuels and Vehicles (PCFV). The PCFV is the leading global public-private initiative promoting cleaner fuels and vehicles in developing countries and countries in transition.

Established at the World Summit on Sustainable Development in 2002, the PCFV brings together 73 organizations representing developed and developing countries, the fuel and vehicle industries, civil society, and leading world experts on cleaner fuels and vehicles. Many developing and transitional countries - through support of the PCFV - have completed the phase-out of leaded petrol, followed by the adoption of targets and roadmaps to introduce lower sulfur fuels.

UNEP also provides advisory services to governments to have measures, policies, or frameworks for air pollution control implementation and enforcement.  This includes support to develop effective legislative frameworks on ambient air quality. UNEP has developed a Guide on Ambient Air Quality Legislation to assist national lawmakers and policymakers to develop or improve ambient air quality legislation and also provide tailored legal assistance through the 'Law and Environment Assistance Platform' (LEAP).

UNEP also strengthens regional cooperation and knowledge sharing, and contributes to the development of robust awareness-raising strategies and advocacy. In Asia Pacific, UNEP hosts the Asia Pacific Clean Air Partnership (APCAP), and provides secretariat services to the Acid Deposition Monitoring Network in East Asia (EANET) and the Thematic Working Group on Air Quality and Health under the Asia Pacific Regional Forum on Health and Environment (APRFHE). 

Globally, UNEP hosts the Secretariat of the Climate and Clean Air Coalition (CCAC) and is setting up a Global Cooperation Network on Air Quality. UNEP also leads efforts through the International Day of Clean Air for Blue Skies held annually on September 7. This event serves as a platform for global collaboration on air quality improvement.