I strongly suspect there are few large settlements worldwide where it's not possible to grow produce either outdoors or in polytunnels to cater for this need. B

I strongly suspect there are few large settlements worldwide where it's not possible to grow produce either outdoors or in polytunnels to cater for this need. But if it were the case, we (humanity) could either move the settlements or allow an exception for the missing essentials. It would still drastically reduce freighting overall.