**6. Recommendations**

The authors believe that improving China's light pollution laws and regulations requires improvements to the legislative model, such as special legislation on light pollution. Depending on the actual situation of each city, light pollution impact assessment should be performed according to clear criteria. For example, Seoul proposes that the mayor should strive to maintain the Korean industrial standard street lighting as the standard for light pollution environmental impact assessment and can seek expert advice accordingly. In addition, special department supervision is needed. For example, Seoul clearly stipulates that the mayor should formulate and implement policies to prevent light pollution and establish a light pollution committee. There should be clear accountability and incentive mechanisms, such as in Seoul, and the mayor may choose to reward those who contribute to the prevention of light pollution [16].

Furthermore, in the actual control, data analysis is needed, and the night sky brightness of different cities is collected to conduct a comparative analysis, and the results are obtained and then controlled point-to-point. For example, Wei Jiang et al. [52] used the Luojia 1–01 satellite to analyze and compare the night sky brightness with the brightness of different degrees in Wuhan, Seoul, Haifa and Mexico.

On the other hand, in future research of laws and regulations, the brightness of the night sky should be compared before and after the data in a range of years, so that the practicability of the current rules can be confirmed—for example, Wei Jiang et al. [53] used the Defense Meteorological Satellite Program Operational Linescan System (DMSP/OLS) for data collection from 1992 to 2012 in assessing light pollution in China based on nighttime light imagery and analyzed the degree of light pollution in various regions of China. It was concluded that China's light pollution has significantly expanded in provincial capital cities in the past 21 years. Therefore, by analyzing this, we can see that the degree of light pollution is on the rise when no relevant light pollution regulations are proposed. In the future, it is necessary to continue collecting proper data to compare and analyze the practicability of current rules on light pollution.

At the same time, in future research, the ecosystem needs to be paid attention to in light pollution. We can also conduct data comparison analysis. For example, Jonathan et al. [54] used DMSP/OLS in combination with GLC2000 to collect nighttime lights from 1992 to 2012 and evaluated the latest changes in nighttime artificial illumination for 43 global ecosystem types. The results indicated that the Mediterranean climate–ecosystem has experienced an enormous increase in exposure and that all terrestrial ecosystem types have experienced a certain degree of artificial light exposure and that this exposure is increasing. Through the analysis of the ecosystem, the relevant laws and regulations can be strengthened in the future.

In the era of big data, we not only need to use data collection but also need to listen to the opinions of the public—for example, the public's views on light pollution and its impact on the environment. Lyytimaki et al. [55] investigated the public's views on light pollution as an environmental problem using a questionnaire survey. Of the 2053 responses to the study, 84.6% said light pollution had spread to all areas. A total of 82.9 per cent of the respondents said it was essential to be dark. Various light pollution sources were found in the problem of light pollution sources. The most commonly mentioned sources were street lamps, courtyard lamps, commercial lights, and outdoor decorative lights. Therefore, the author believes that only by combining a questionnaire survey, interviews, and DMSP/OLS data collection, etc. can the occurrence of light pollution be effectively controlled, and the effectiveness of laws and regulations be improved in the future.
