As different pollutants would result in different adverse health and environmental impact (e.g. emissions from diesel vehicles are carcinogenic, Particulate Matter (PM) pollutant is associated with decreased lung function, development of chronic bronchitis, stroke and premature death, Nitrogen Oxides (NOx) pollutant leads to the production of more ozone which inadvertently impair respiratory functions, etc.), it is not appropriate to trade off one pollutant for another through a weighted average system. Vehicles that contribute significantly to any one pollutant should not be incentivised under VES. By basing the rebate/surcharge on the worst-performing pollutant, only vehicles with low tailpipe emissions across all pollutants will be incentivised. This will better enable us to achieve our World Health Organisation (WHO) air quality and carbon dioxide (CO2) targets for 2020 and 2030.