Shaunna you are right, 'non-motor vehicles affecting the "tidiness" of the streets", can we just summarize it as 'violation of parking regualtions or control'.

I think 环境卫生 here is being used rather loosely (typical of Chinese government-speak). Strictly speaking, 环境卫生 corresponds to environmental sanitation, which mainly deals with maintaining public hygiene, preventing infectious diseases and thus safeguarding people's health (more often than not the image of street cleaners pop up upon seeing 环境卫生 or briefly 环卫, actually they should be broadly and politely called sanitary workers.) But here, regulating the parking of non-motor vehicles more likely belongs to the work scope of city appearance maintenance corps, in Chinese 市容 (city appearance) or broadly 城管 (city management)。

世卫组织环境卫生报告：
http://www.who.int/water_sanitation_health/hygiene/emergenci...

上海市容管理局，上海市环卫局英文网站（其中的译法可能不太规范，但明显区分了“市容”与“环境卫生”，奇怪的是没有对应的中文网站）
http://www.sh1111.gov.cn/WebFront_EN/index.aspx

However, I still doubt if "environmental sanitation" includes "city appearance maintenance", if yes, then simply "environmental sanitation" would do.