City MPG
Fuel economy in stop-and-go urban driving, usually the lowest of the three EPA figures.
City MPG reflects stop-and-go driving with frequent acceleration and idling, simulated on the EPA's urban test cycle. For most gasoline cars it is the lowest of the three ratings because accelerating from a stop burns the most fuel.
Hybrids flip the pattern: regenerative braking recovers energy in traffic, so many hybrids post a better city figure than highway figure. If most of your miles are urban, the city number is the one to compare.