Belgium introduced a traffic light system earlier this week. Travel to red areas is not permitted, and if you happen to be there when it got the red code, you will be obliged to self-isolate and to undergo a corona test: a first one when you return, and a second one after 9 days. No matter what the result of the first test is, you will have to isolate. If you don't, you risk heavy fines.
The amber code is less clear about consequences. The government advises against travelling to an amber area, but corona testing and self-isolation may only be "recommended" when you come back. Click here to check about each case specifically.
So far, four areas have been colour-coded red: apart from Leicester, it's Lisbon (Portugal) and A Mariña and Leida (Spain). Leicester has recently seen a flare-up of Covid-19.