AdBlue Explained: Guide to Cleaner Diesel Cars

What is AdBlue? 

AdBlue is a special fluid used in BS6 diesel vehicles to help make them cleaner and more eco-friendly. It’s not a fuel additive but a clear liquid that plays a key role in reducing pollution.

What is AdBlue Made Of?

AdBlue is made from high-purity urea and de-ionized water. Modern diesel cars have a separate tank for AdBlue. This fluid works with Selective Catalytic Reduction (SCR) technology to cut down on harmful gases. Some cars use a different tech called Lean NOx Trap (LNT), which is cheaper but still effective in lowering emissions. However, models like the Mahindra XUV300 use SCR, which means they need AdBlue.

How Does AdBlue Work?

Here’s a simple breakdown of how AdBlue works:

  1. Injection into the Exhaust: AdBlue is injected into the car’s exhaust system before it reaches the SCR catalyst.
  2. Chemical Reaction: Once in the exhaust, AdBlue heats up and breaks down into carbon dioxide and ammonia. These then react with harmful nitrous gases, turning them into harmless nitrogen and water, which come out as steam.

Why is AdBlue Important?

AdBlue helps diesel cars reduce their NOx emissions, which are harmful to the environment. By using AdBlue, cars can meet strict emission standards and pollute less. It’s said that AdBlue can cut down more than 90% of these harmful gases.

How to Use AdBlue

Tank Capacity and Indicators

AdBlue tanks usually hold between 5 to 20 liters, depending on the car. The tank’s capacity is often mentioned near the fuel tank lid or in the car’s manual. As you drive, you might need to top up the AdBlue, usually done during regular car services. There’s also an indicator on the car’s dashboard that shows how much AdBlue is left.


In India, AdBlue costs between Rs. 85 to 100 per liter.

Other Things to Know About AdBlue

Your car won’t stop immediately if the AdBlue runs low, but it might lose power until you refill it. If you stop the engine when the AdBlue is empty, you might not be able to restart it until you add more. You can buy AdBlue online or at various stores, but it’s best to get it refilled at your car dealership.

AdBlue is super important for keeping diesel cars clean and meeting today's strict emission rules. It’s a small step that makes a big difference in protecting the environment.

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