Rapid decline in gas mileage

Ive got a 2024 that I bought in august I’ve consistently gotten 25-27 per gallon fuel milage for CITY driving in eco or normal mode with a few brief stints in N mode In the last few months. In the last week my fuel mileage has dropped DRASTICALLY. We’re sitting at 21-22 only driving it in eco mode. What’s the most common cause for something like this?