1

Advancing Cambodia’s Leadership in Low-Emission Vehicles

by Climate and Clean Air Secretariat - 3 September, 2025

Cambodia’s economy is expanding at a steady pace, and with it comes the likelihood of rapid motorization. Today, the country’s roads are dominated by imported vehicles—nearly 90 percent of them used and sourced from abroad. Two- and three-wheelers make up the majority of the fleet, but as incomes rise, the market is expected to shift toward larger and more fuel-intensive vehicles.

This transition carries risks. Cambodia is already the only country in ASEAN where average CO₂ emissions from imported light-duty vehicles are still increasing. Projections show they could reach 325 gCO₂/km by 2030 without intervention. At the same time, the average age of imported vehicles is climbing, with more than 60 percent now over ten years old. Between 2012 and 2016 alone, the average fuel economy of imported vehicles worsened from 9.34 Lge/100km to 10.20 Lge/100km, and is on track to triple the 2030 Global Fuel Economy Initiative target if left unchecked. 

 

Choosing the right vehicles—and fuels 

As Europe, North America, and other regions transition to cleaner fleets, their older, higher-emitting vehicles often find a second life in developing markets. Without strict import regulations, Cambodia risks becoming a dumping ground for polluting vehicles that release not only CO₂ but also short-lived climate pollutants such as black carbon.

To get ahead of this trend, Cambodia has committed to implementing Euro IV vehicle emission standards for all new and imported second-hand vehicles starting in 2022, followed by Euro V in 2027. These policies require the use of low-sulfur fuels—essential to ensuring that modern engines and emissions controls function properly. As a fuel-importing country, Cambodia must therefore enforce strict sulfur limits and ensure quality monitoring systems are in place to protect both engines and air quality. 

 

Coordinating standards for success

Rolling out cleaner vehicle standards is only possible if cleaner fuels arrive at the same time. Euro IV vehicles cannot operate on high-sulfur fuels without damaging their engines, making coordination between the two policies critical. With CCAC’s support, UNEP has provided technical guidance to help Cambodia design an effective Euro IV implementation plan and prepare a roadmap for Euro VI, announced in a recent ministerial declaration.

Still, significant challenges remain. Enforcement capacity within the Ministry of Environment is limited, with critical gaps in legal authority for roadside inspections, technical equipment, trained personnel, and cross-agency coordination. Even where low-sulfur fuel standards are adopted, monitoring systems are costly and difficult to maintain. Recognizing this, Cambodia is prioritizing investment in fuel quality monitoring systems—a key area where CCAC and UNEP are now providing additional support. 

 

From policy leadership to new opportunities 

Cambodia’s proactive approach positions it as a regional leader in vehicle emissions standards, moving faster than many of its ASEAN neighbors. Its commitments send a clear signal to importers, fuel suppliers, and the public that cleaner vehicles and fuels are the future. Building on this foundation, the government has expanded its focus to include heavy-duty vehicles, supported by a new CCAC grant, and recently introduced incentives for electric motorcycles and tuk-tuks.

By tackling vehicle emissions early, Cambodia is not only protecting public health and air quality at home, but also setting an example for the region. With CCAC’s support, the country is charting a path toward a cleaner, more sustainable transport system—proving that even in fast-growing economies, the right policies can steer growth in a healthier direction. 

1

Related projects