In a U-turn, the National Environment Agency (NEA) has said petrol vehicles with port fuel injection will not be exempted from particulate matter (PM) tests for the Vehicular Emissions Scheme after all.

It announced yesterday that after receiving feedback and analysis, it decided that such vehicles would now be subject to all five pollutant tests as part of the scheme, which dishes out tax rebates or surcharges according to a car's emission levels.

Earlier this month, The Straits Times reported that some carmakers and dealers were unhappy over a surprise move by NEA to exempt some models from getting PM readings. They felt it would create unfair competition. NEA said then that petrol models with port fuel injection - where fuel is injected just before the engine's combustion chamber - were deemed to have "very low" PM emissions under European emission standards.

The scheme starts from Jan 1 next year, but car dealers will be given extra time to submit PM emission readings for port fuel injection vehicles, which will be banded under the scheme from July 1.

The honourable adviser to the Automobile Importer and Exporter Association, Mr Neo Nam Heng, said dealers are confused by NEA's conflicting messages. Mr Derek Low, director of dealership Venture Cars, said: "We thought everything was settled already... we had plans for what cars to import next year when the scheme kicks in, but now it seems like we have to rethink those. NEA should stick to what it proposed, not succumb to pressure. "

• Additional reporting by Tiffany Fumiko Tay