Is it illegal to throw cigarette butts downstairs?

It belongs to high-altitude parabolic objects and is suspected of infringement. You can ask for removal and apologize.

If you deliberately set fire by throwing cigarette butts, you are suspected of arson. If it's just like throwing garbage, it's a mistake. If the circumstances of the fire caused by negligence are serious, it constitutes a crime of fire failure; Fire caused by negligence, which does not constitute a crime, shall be detained for more than 10 days and less than 15 days, and may be fined up to 500 yuan; If the circumstances are minor, a warning or a fine of not more than 500 yuan shall be imposed. It may also constitute a crime of endangering public safety in a dangerous way. Specifically, it is necessary to investigate whether the location where the parabolic objects and falling objects occur belongs to public places, whether there may be potential victims of unspecified majority, and more importantly, whether the nature of the parabolic objects and falling objects is enough to cause power that harms most people. Falling objects are not enough to endanger the life, health and property safety of unspecified majority, and cannot constitute the crime of endangering public * * * by dangerous means.

Legal basis: Article 1254 of the Civil Code of People's Republic of China (PRC) prohibits throwing objects from buildings. If an object thrown from a building or an object falling from a building causes damage to others, the infringer shall bear tort liability according to law; If it is difficult to determine the specific infringer after investigation, in addition to being able to prove that he is not an infringer, the user of the building who may cause harm shall be compensated. After compensation, the user of the building who may cause damage has the right to recover from the infringer.