Why is my Kia Ceed's fuel efficiency decreasing?

I noticed that my Kia Ceed's fuel efficiency has been decreasing recently. What could be causing this and how can I improve it?

It is possible that your car's spark plugs may need to be replaced. Consider scheduling a maintenance check-up with a certified mechanic.

Another potential cause could be low tire pressure. Make sure to regularly check and maintain proper tire pressure for optimal performance.

It's also worth checking your air filter, as a dirty air filter can decrease fuel efficiency. Consider replacing it if it appears dirty.