Shops have managed to cut the amount of plastic bags that we use by nearly half.
Last year seven supermarkets said they'd try to cut the amount of bags given to customers compared to how many they gave out in 2006.
In May 2006, 718m bags were being given out, but by May 2009 this had almost halved to 372m.
Plastic bags harm the environment because they take a long time to decompose and can endanger wildlife.
Plastic bags can end up in landfill sites
Although plastic bags don't actually make up much of the rubbish and pollution we make, campaigners still think this plan is important.
That's because cutting back on bags shows how we can change the way we act if we put our minds to it, something that could be important if we want to fight climate change.