**1. Introduction**

Light pollution is one of the most rapidly increasing forms of environmental degradation. There is increasing evidence that draws potential linkages between artificial light at night (ALAN) and certain human health conditions. For example, a study by Rybnikova et al. [1], based on World Bank databases, reported a statistically significant association between ALAN and prostate cancer incidence. A potential correlation between outdoor LAN and breast cancer incidence was also reported by Peter et al. [2]. In addition, ALAN has been linked to diabetes [3], fatigue, and depression [4]. In addition to the effects of ALAN on the well-being of humans, sky glow resulting from ALAN is a major interference to astronomical activities [5,6]. Furthermore, excessive and unnecessary ALAN is a key contributing factor to energy waste [7].

As such, these rapidly increasing adverse effects of ALAN on humans and the general interactions between ecosystems have led to subsequent legal actions against improper usage of light, especially at night. The involvement of governmental institutions, in the form of ordinances or laws against ALAN, has increased over the years [8]. Light pollution laws, ordinances, and prescriptive measures are becoming common in many parts of Europe [9], Asia [10,11], and America [12].

Although the effects of ALAN are primarily the same in all areas, different countries have adopted diverse legal approaches to reduce light pollution. For example, as discussed by Martin-Taylor [13], the United Kingdom has extended the previously existing law on air pollution to include light pollution. Many Italian regions have employed individual ordinances to prevent or reduce specific light-related issues prevalent in given regions [14]. There is a variety of factors that influence the type of light pollution laws employed by a country or region. For instance, bolt-on laws are likely to be less

expensive than stand-alone laws adopted for the specific issue of light pollution [12]. In addition, ordinances are likely to provide better solutions in countries with cities or regions that experience diverse forms of light pollution [14]. China and Korea are among the countries that recently established light pollution preventive measures through city ordinances. Given the social similarities between China and Korea, which may give rise to similar artificial lighting trends, the current study provides a comparative analysis of the Seoul light pollution ordinance and the regional light pollution laws and preventive measures in China. The contents of this study provide an extensive technical guideline to countries or regions that wish to draft their own regional or city-based light pollution laws.
