Why is the gas mileage on my Nissan Micra not as good as it used to be?

I've noticed that the gas mileage on my Nissan Micra has decreased significantly in the past few months. What could be causing this and how can I improve it?

There are several factors that could be causing this decrease in gas mileage. One possibility is that your tires may be underinflated, which can decrease fuel efficiency. Check the pressure and make sure they are filled to the recommended level.

Another potential cause could be a clogged air filter. This can restrict the airflow to the engine and decrease gas mileage. Consider replacing the air filter if it has not been changed in a while.

Have you been using the air conditioning more frequently? Running the AC can significantly decrease gas mileage. Try turning it off when you don't need it.