We are all familiar with the theory of negative externalities, and examples are not difficult to find. However, the weekend takeaway is not an obvious one. The externality seems to lie in the container, rather than the takeaway, and the fact that they are often made of a non-recyclable plastic such as styrofoam which will contribute towards landfill and associated environmental problems. It seems that the authorities in Oxford are taking steps to solve the problem as this article shows:
For us as economists this demonstrates a regulation approach, rather than a market mechanism such as a tax on the containers. It will be interesting to evaluate the results.