The emission standards are set by the European Union, and impose strict rules on tailpipe gases of new vehicles sold in EU member states. It has also been progressively implemented in Singapore and other countries.
Singapore's move towards Euro 6 is yet another effort to reduce fine particulate matter in the air - a serious health hazard.
The Ministry of the Environment and Water Resources, responding to queries from The Straits Times, explained that the aim was "to address the concern that recently popular compression injection diesel engines and gasoline direct injection engines actually increase the emissions of ultra-fine particulates".
These ultra-fine particulates make up the bulk of particulate emissions and are very small and light.
Apart from tightening up on particulate emissions, the Euro 6 emission standards will also reduce emissions of nitrogen oxides - another harmful air pollutant - said the ministry.
Although the ministry said that it has not arrived at an implementation date, motor industry players said they have been informed of a rollout in the second half of 2017.
While European brands are confident that they will be able to meet such a deadline - all new European cars registered from January will have to be Euro 6-compliant to meet EU requirements - it may be a challenge for the Japanese, as there is currently no equivalent standard in Japan.
A Toyota Motor Asia-Pacific spokesman said: "We are reviewing our product strategy while working closely with the Japan Automobile Manufacturers Association, who we understand has provided input to the National Environment Agency."
Mr Vincent Ng, product manager at Honda agent Kah Motor, said: "Honda has indicated that a three-year notice would be a comfortable timeline." That means it needs formal written notice about now.
A BMW Asia spokesman added: "Currently, about 95 per cent of our portfolio is Euro 6-compliant. Only some models require updates... but all are scheduled to be compliant by end-2015." Mr Neo Nam Heng, president of the Automobile Importer and Exporter Association, said that it has been told of the 2017 implementation.
But he stressed that all major players must be able to meet that deadline, "otherwise we will have another big headache".
He was referring to the 2006 rollout of Euro 4 for diesel vehicles. The Japanese were not ready then, and that led to a crash in the certificate of entitlement (COE) prices. With that, thousands of commercial vehicle owners extended the lifespan of their ageing fleet - many of which are still on the road today.
The ministry said that it is mindful of the lessons learnt in the 2006 experience, which will be taken into account for all upcoming measures.
While the motor trade has been told of a 2017 target, it seems oil companies - whose products such as petrol and diesel also have to burn more cleanly under the new standards - have a longer time to comply. Currently, such products here need meet only Euro 4 standards.
The Straits Times understands that oil companies have up to January 2018 to meet the Euro 5 standard for diesel. For petrol, they have up to December 2018. "So far, there's been no word on Euro 6," an industry source said.
Asian Clean Fuels Association executive director Clarence Woo said it is crucial to reduce particulate matter, "some of which are so fine they can enter your body through your skin".
He added that other pollutants such as nitrogen oxides should also be reduced drastically, as these can "lead to secondary formation of particulate matter".
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