The main reason why the rules are there is because hanging clothes (even without underwears) is considered unsightly and might reduce public perception of the building and unit value. Silly? Maybe. But if you don't abide they can impose a penalty you for not abiding to the by law.
Is it an older building? The newer building usually have more lenient rules, e.g. if the washing is not visible from the road, then you can hang it there.
Is it an older building? The newer building usually have more lenient rules, e.g. if the washing is not visible from the road, then you can hang it there.