Why is my Kia Niro's fuel mileage decreasing?

I've noticed that the fuel mileage on my Kia Niro has been decreasing over time. What could be causing this and how can I improve it?

One possible reason for the decrease in fuel mileage could be that your tires are not properly inflated. Make sure to regularly check the tire pressure and adjust it to the recommended level.

Another reason could be that your air filter is dirty and needs to be replaced. This can affect the efficiency of your engine and result in lower fuel mileage. Consider replacing the air filter every 15,000-20,000 miles.

Have you been using premium gasoline? While it may seem like a better option, it can actually decrease fuel mileage in some vehicles. Check your owner's manual to see the recommended grade of gasoline for your Kia Niro.