Box delivery schemes which deliver seasonal, organic food to your door vary greatly.
Some deliver just fruit and vegetables, others include meat, groceries and other household goods.
Some grow all their own produce and deliver locally. Others buy produce from a wholesaler, much of which could be imported, and deliver over a wide area. Some give assurances that no air freight is involved. Check your scheme’s policies before you sign up.
In general, the more local, seasonal and organic the scheme, the better it is for the climate, saving on transport, greenhouse energy and emissions from the manufacture and use of fertilisers.