There are two ways for diesel engine manufacturers to meet ever-stringent standards on nitrogen oxide emissions: Apply a costly urea-based exhaust treatment system, or cheat.

In the C4 Picasso BlueHDi, Citroen has chosen the former method. The 1.6-litre turbodiesel is the smallest diesel engine here to have AdBlue, the urea-based solution that is injected into the exhaust to neutralise NOx. It allows the car to comply with Euro 6, the most stringent European emission standard.

The system is estimated to add $10,000 or more to the cost of a car in Singapore, after taxes.

But because the car qualifies for $15,000 in carbon rebates, it is priced competitively against a Japanese 1.6-litre petrol sedan.

At about $116,000, the Citroen is quite a lot of bang for the buck. It is not as big as the seven-seat Grand Picasso, but it is still an MPV-shaped vehicle. That means a high ceiling, taller seating position and waist-level stowage area.

Its wheelbase of 2,785mm is longer than a Toyota Camry's. With a completely flat floor, occupants in the second row have more legroom than in some big luxury cars.

And unlike most five-seaters, the C4 comes with three individual seats in the back. That means the person in the middle gets as comfortable a ride as the other two.

Talking about comfort, this Citroen is French-like in the ride department. You get a nice blend of firmness and cushiness, with dampers that cushion the harshest humps. Take it around a corner and the chassis holds up well, tackling the manoeuvre with neutrality, enviable traction and just a whiff of body roll.

What contributes even more to comfort is the six-speed Aisin transmission that is paired with its 300Nm turbodiesel power plant.

Compared to the semi- automatics that French manufacturers are fond of using, the Aisin autobox is sheer satin.

The gearbox is tuned more for efficiency than urgency. If you are driving a 1.6-litre petrol model now, you are likely to halve your visits to the pump if you switch to the C4.

That should more than offset its annual road tax of $1,344, which is more than double the $607 you would pay for a petrol model with an identical engine displacement.

Like most diesels, the engine is super torquey, but is more enjoyable than most because it is so refined.

The C4 is a joy at the wheel for another reason - its extra-wide Zenith windscreen. Besides better visibility, you also get a brighter and airier interior.

The car is equipped with a 7-inch infotainment monitor that includes navigation and Bluetooth connectivity. You can hook your i-devices to it via a USB port. It has cruise control, six airbags and keyless access and ignition.

Also, there is a centre console with neat compartments - including one that holds most phones upright. This console is removable, so you can have a walk-through aisle if you wish.

The only thing that is slightly off is its tailgate, which is rather heavy and has a somewhat slippery grip. But it is a tiny trade-off for such a creditable package.