What is the ruling on working in the delivery of non-halal foods, or in a grocery store that sells forbidden items to those in need?

It is not permissible to work in delivering prohibited foods due to the assistance it provides in sin. However, working in grocery stores that sell some prohibited items, such as cigarettes, is permissible if one restricts oneself to selling only the permissible items. But if you are in need of work and cannot avoid selling cigarettes, we hope that there is no sin upon you until you can find another permissible job.