CNG vs petrol vs diesel: Which car is better for purchase?

Team AckodriveJun 6, 2022

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A car purchase decision involves considering several factors, and one of the most important factors is the car fuel type. It is crucial to decide which fuel type you want to go with, even before shortlisting the potential options. The car's mileage, running cost, and maintenance costs vary depending on the fuel type you choose. Hence, knowing which is the right fuel for your requirements is crucial. In this article, let's discuss one of the hot topics of the Indian automobile industry: CNG vs petrol vs diesel cars.

CNG vs petrol vs diesel

Which car is best: petrol or diesel or CNG?

The Indian automobile market is known for its budget-friendly, value for money and fuel-efficient cars. The Indian buyer sentiment is such that mileage or fuel economy always takes the front seat when buying a new car. Hence, fuel-efficient CNG, petrol and diesel cars are popular in India. But which car is best for you? To answer this question, you need to understand the key differences between diesel, petrol, and CNG cars.

Glance through the table below to better understand petrol vs diesel vs CNG cars.

Note: The below comparison assumes that the cars have similar engine capacity (cc) and belong to the same segment.

Parameters Petrol car Diesel car CNG Car
Fuel price High Lower than petrol Low
Car price Affordable than diesel and CNG cars. More expensive than petrol and CNG cars. More expensive than petrol cars, but affordable compared to diesel cars.
Performance It offers good performance with better pick up than diesel and CNG cars. Slower initial acceleration but offers good top-end performance. Lower power output than petrol and diesel cars. Also, you may experience a slight lag in power delivery.
Comfort Petrol engines are refined, and the NVH (Noise, Vibrations, Harshness) levels are low inside the car. Hence, they offer a comfortable driving experience. Diesel engines are less refined than petrol. Hence, the NVH levels are higher inside the cabin. Since CNG cars run on petrol-compatible engines, the refinement is on par with petrol cars.
Boot space Spacious Spacious It is non-existent since the CNG fuel tank eats up the boot space, which may be not practical for long drives.
Mileage Lower than CNG and diesel cars. Higher than petrol cars, but lower than CNG cars. Higher than petrol and diesel cars.
Running cost High Lower than petrol cars, but higher than CNG cars. Low
Maintenance cost Higher than CNG cars but lower than diesel cars. High Higher than petrol and diesel cars due to the fitment of CNG kit.
Environmental friendliness It is not environment-friendly as the exhaust gas comprises carbon monoxide. It produces carbon emissions. They are environment-friendly as the fuel is completely combustible and produces clean emission.
Fuel availability Easily available Easily available CNG fuel stations are not easily available as petrol or diesel fuel stations.
Engine life Lower than diesel engines. Diesel engines last longer than petrol engines. The engine life is similar to petrol engines.

CNG vs petrol vs diesel mileage

CNG cars are the most fuel-efficient out of the three fuel type cars. In contrast, diesel cars offer better fuel economy than petrol cars. However, they cannot match the mileage of CNG cars. Petrol cars are the least fuel-efficient. However, the fuel efficiency depends on your driving style. For instance, if you drive a diesel car aggressively, you cannot expect good fuel economy.

Also, read: Best mileage petrol/diesel cars/SUVs in India

CNG vs petrol vs diesel engine life

When it comes to engine life, diesel cars take the honour. A diesel engine lasts longer than petrol and CNG-powered engines. That’s mainly due to diesel’s fuel properties. Diesel is a volatile fuel, and it also lubricates the engine components. Hence, a diesel engine will last longer than its petrol and CNG counterparts.

Petrol and CNG engines have similar engine life, which is lesser than diesel engines. One common myth related to CNG cars is that CNG fuel reduces engine life. But in reality, it is not the case. CNG fuel does not damage the engine components despite having different fuel properties than petrol/diesel. Hence, petrol and CNG engines have a similar life.

CNG vs petrol vs diesel car maintenance

Petrol engine cars are cheaper to maintain as the engine spare parts are affordable. On the contrary, diesel engines have complex components. Hence, the spare parts price also goes up. Overall, diesel cars are more expensive to maintain than petrol cars.

CNG cars run on bi-fuel petrol engines. That means you can drive the car with petrol or CNG fuel. Now you may think that the maintenance costs are similar to petrol cars. But it’s not the case here. Since a CNG car has a CNG kit and an engine, the maintenance costs are high. The maintenance cost of a CNG car also depends on the quality of the kit. They also require frequent checks to identify any leak in the system. Hence, the overall maintenance costs can run high, even higher than petrol and diesel cars, if the vehicle is not maintained correctly.

Advantages of CNG, petrol and diesel cars

Below are the advantages of petrol, diesel and CNG-powered vehicles.

Pros of CNG cars

Here are some of the benefits of CNG cars.

  • CNG cars have a low running cost compared to petrol and diesel cars. The reason for that is the low fuel price. CNG costs way less than petrol and diesel fuel.

  • CNG-powered cars return a high fuel economy.

  • Cars running on CNG fuel are environment-friendly. They do not produce carbon emissions.

  • CNG cars give you the flexibility to use two fuels: CNG and petrol.

Also, read: Best CNG cars in India

Pros of petrol cars

Below are the advantages of petrol cars.

  • Petrol cars are cheaper than CNG and diesel cars.

  • Low NVH levels result in a comfortable driving experience.

  • Petrol cars deliver better low-end performance, and the overall power output is stable.

  • Lower maintenance costs.

Pros of diesel cars

Here are the advantages of diesel cars.

  • The running cost is lower than petrol cars.

  • Diesel cars have better top-end performance. Hence, they are ideal for long highway drives.

  • A diesel engine lasts longer than a petrol engine.

  • A diesel car delivers high fuel efficiency compared to a petrol car.

Also, read: Top diesel cars in India

Disadvantages of CNG, petrol and diesel cars

In this section, let’s glance through the disadvantages of petrol, diesel and CNG cars.

Cons of CNG cars

Below are some of the cons of CNG-powered cars.

  • CNG cars deliver low performance in comparison to petrol and diesel cars. You feel the lag when you press the throttle, and that’s not one of the best driving experiences.

  • The CNG fuel tank (cylinder) capacity is low. Hence, the full-tank driving range is compromised.

  • CNG vehicles have no boot space as the CNG cylinder takes up that space.

  • The lack of CNG fuel stations makes refuelling a hassle.

  • CNG cars are expensive due to the addition of CNG kits.

  • Higher maintenance costs.

Cons of petrol cars

Here are the demerits of petrol cars.

  • Higher running costs due to the higher fuel price.

  • The torque and high-end performance are lesser than diesel engine-powered cars.

Cons of diesel cars

Below are some of the disadvantages of diesel cars.

  • Diesel cars command a higher price tag.

  • NVH levels are high, and the engine is not refined like petrol cars.

  • Higher maintenance and spare part costs.

Petrol vs diesel car, which is better

Now, you know the advantages and disadvantages of petrol and diesel cars. So, which one makes a better choice for petrol vs diesel cars? The answer to this question depends on your driving requirements.

If you need a car for long-term usage, and your average driving distance is on the higher side, a diesel car might be a sensible choice. On the other hand, if you plan to upgrade your car in a few years, and your average driving distance is significantly less, then you can go for a petrol car.

CNG car vs petrol car

The next question on your mind would be, which is a better choice in terms of CNG vs petrol car? Since both types of cars run on petrol engines, it may be a tricky choice. But to make it simpler, let’s put it this way. If you need a daily-driver car, a CNG car makes a lot of sense. A petrol car will be a good choice if you need a car for daily commutes and long drives.


There is no specific answer to the question: Which is a better fuel type? Because the choice depends on your requirements. Below are some key points to consider when deciding on the car fuel type.

  • If you are looking for a car with overall good performance, can munch miles easily, and lasts long, diesel cars are best for you. 

  • If you wish to own a car with low maintenance and enough grunt under the bonnet, petrol cars are the best. 

  • Lastly, CNG cars are the way to go if you need a vehicle for daily commutes with low running costs. Plus, CNG cars are also eco-friendly. Hence, you do not pollute the environment when driving a CNG car.

Frequently Asked Questions (FAQs)

Let’s look at some of the most common queries regarding petrol vs diesel vs CNG cars.

Is CNG fuel cheaper than petrol and diesel?

Yes, CNG fuel is cheaper than petrol and diesel. Hence, the running costs of CNG cars are on the lower side.

Are CNG cars environment-friendly?

Yes. CNG-powered cars do not produce carbon emissions like petrol and diesel cars. So, they are eco-friendly.

Does CNG fuel damage the car’s engine?

No, CNG fuel does not cause any harm to the car’s engine. It’s a common myth that CNG reduces engine life. But it’s not the case.

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