Euro-4 level is the second strictest emission measurement of the European Emission Standards. To reach this level,
vehicle emission of Carbon Monoxide (CO), Hydrocarbon (HC), Nitrogen Oxide (NOx) should be 1 g/km or below (pls see table below).
All new vehicles sold in European countries should meet at least Euro-4 level, otherwise they will not
be allowed on the roads.
Some countries in Asia & Oceania such as Australia and India have adopted the Euro-4 level conformity. The
Philippines on the other hand has adopted only up to Euro-2 level.