Why is the fuel efficiency of my Kia Niro decreasing?

I recently purchased a Kia Niro and noticed that the fuel efficiency has been decreasing. What could be causing this and how can I improve it?

Have you been driving in stop-and-go traffic frequently? This can greatly affect your fuel efficiency and it may be helpful to try alternative routes that have less traffic.

Check your tire pressure regularly. Low tire pressure can increase fuel consumption and reduce your car's efficiency.

Make sure your air filter is clean. A dirty air filter can restrict air flow and decrease fuel efficiency.