The California Air Resources Board (CARB) has today agreed to reduce the number of zero-emissions vehicles carmakers are mandated to build each year by 70%, easing an earlier target that would have seen them sell up to 25,000 zero-emissions vehicles between 2012-2014. This figure has now been reduced to just 7,500, and only the top six carmakers have to meet the new regulation.

While the reduction may seem like a backwards step, the board is in instead focusing on viable technologies by increasing quotas for fuel-efficient vehicles such as hybrids and plug-in hybrids. In fact, from 2012 to 2014, the CARB has imposed a requirement on carmakers to sell a sizeable 66,000 plug-in hybrids.

The switch of focus to more complicated plug-in hybrids rather than zero-emission vehicles or non plug-in hybrids makes sense - if you're only driving short distances to and from work and around town, the car essentially becomes a zero-emissions vehicle as it will have enough power from its own battery. Proper-zero emission vehicles, meanwhile, are still some while away as manufacturers rush to reduce the high costs of fuel-cells and battery packs, currently the largest factor in the industry’s inability to release the clean vehicles to the market in high volumes.

Pictured above is the Karma luxury plug-in hybrid from California’s Fisker Coacbuild. The car is powered by a small petrol engine and an electric motor and can drive up to 50 miles on electric power alone.