Mobile detailing service in eastern europe, using steam for outside cleaning question

Hello detailing community! Throughout the years I managed to save up some money in hopes that I can start a small business and work independently. For the past weeks I've been researching stuff about mobile car detailing and a bunch of other small business ideas, and I really enjoy this one.

The main problem that I stumbled upon is that in Europe there are local laws, at least in my country (eastern europe) which don't allow you to clean outside non private areas with chemicals and shampoo. The mobile detailing business is very niche and there are very few people doing it from what I can see, and unfortunately, a big portion of the population don't really have garage or in-house parking spots, as they mainly park their cars on public streets or streewtalks.

So with this in mind, I saw that there is a very niche part where some people are doing an eco-friendly way and steam the exterior of cars.

If someone could share some knowledge regarding this I would really appreciate it!

I'd mainly like to try and do both things supposedly, offering the choice between power washing with shampoo if someone has a garage or private property with a parking or garden area, and if there isn't, offer the choice to clean the exteriors using steam.

Does this seem worth to you, or should I just drop the idea of exterior steam, and just offer interiors if there is no private property?

Thank you!