I wish we would go back to having to bring our own containers and fill them up instead of single use plastics. It's so clearly a terrible thing. Whatever we can do to stop single-use containers we should.
https://www.plasticstoday.com/packaging/just-salad-s-reusabl...
The hygiene part is rather interesting. The people working with the food are not allowed to touch your bowl with their gloved hands, and your bowl can’t touch anything behind the counter. They set a plate on the counter that you set your bowl on, and then they grab the plate and steady your bowl with tongs that they clean after each salad they make anyway. Going back to reusable in restaurant settings would require thinking about the hygiene of those reusables.
The hygiene and manpower implications of bring-your-container easily makes that complicated.
Maybe standardized containers could work. It would certainly be practical if all boxes had the same size :)
So the only viable option becomes reusable containers aka glass containers which lets manufacturers control the cleaning with a supply chain - this is still big for soft drinks sold from restaurants in India. However they're very heavy vs. plastics and both actual cost and the carbon cost of transporting them are probably unfavorable.
It's not really an easy problem to solve though reduction in consumption of packing plastics is definitely possible