Earlier this month, Maruti Suzuki announced that it retailed over 1 lakh (100,000) CNG vehicles in a fiscal year. The exact number was 106,443; the highest ever in a financial year. A week later, the Indo-Japanese firm introduced BS6-compliant (Bharat Stage 6) CNG (Compressed Natural Gas) variants of the Celerio. And now, the S-Presso has received the same dual-fuel setup. Factory-fitted CNG kits are available in four derivatives, ranging between Rs 4.84 lakh and Rs 5.135 lakh, without taxes.

Powering them is a 1.0-litre, three-cylinder motor which, when fed with petrol, produces 67bhp/90Nm. With CNG as the chosen fuel for combustion, that figure drops down to 58bhp/78Nm. The only transmission option is a 5-speed manual, and Maruti Suzuki claims that the mileage on CNG can go as high as 31.2km/kg.

That’s not very interesting, is it! However, if you rope in some maths, things do pick up a bit. The same CNG powertrain also does duty in two other Maruti Suzuki models – the Celerio and the WagonR. With the same power/torque numbers, mileage figure for the former goes only as high as 30.67km/kg. The WagonR, on the other hand, returns a maximum of 32.52km/kg. Do you think this has to do with the kerb weight? Get this – the WagonR clocks between 905-910kg; the Celerio – 920-925kg; and the S-Presso around 750kg.

Something doesn’t add up there. None of the three models is exceptionally aerodynamic, so that goes out of the equation. The Celerio is the heaviest and hence returns the worst fuel economy. But how can the S-Presso CNG be less fuel-efficient than the second-heaviest WagonR? Considering that all three models have the same powertrain, the S-Presso should return the best-possible mileage on CNG.

The Maruti Suzuki S-Presso CNG is available in LXI, LXI (O), VXI and VXI (O) trim levels. In terms of features, they pack everything that their petrol-only counterparts offer. So, with all those facts and figures in place, would you buy the S-Presso CNG over others, which also includes the Hyundai Santro?