北京地铁禁止饮食，合理么？

Beijing just issues the first draft of Beijing Subway Safety Law, which stipulates that passengers who eat in subway elevators, walkways and carriages can be fined up to 500 yuan. Many people are very supportive, while some others express their concern about the feasibility. Actually, this is a comprehensive regulation. Before we talk about the controversial terms, let's just go through it. What does it aim to do?