Estimating treatment effect in randomized trial after control to treatment crossover using external controls.

In clinical trials, it is common to design a study that permits the administration of an experimental treatment to participants in the placebo or standard of care group post primary endpoint. This is often seen in the open-label extension phase of a phase III, pivotal study of the new medicine, where the focus is on assessing long-term safety and efficacy. With the availability of external controls, proper estimation and inference of long-term treatment effect during the open-label extension phase in the absence of placebo-controlled patients are now feasible. Within the framework of causal inference, we propose several difference-in-differences (DID) type methods and a synthetic control method (SCM) for the combination of randomized controlled trials and external controls. Our realistic simulation studies demonstrate the desirable performance of the proposed estimators in a variety of practical scenarios. In particular, DID methods outperform SCM and are the recommended methods of choice. An empirical application of the methods is demonstrated through a phase III clinical trial in rare disease.

Green finance reform and application intensity of chemical fertilizer and pesticide: policy evidence from China.

The environmental hazards resulting from the excessive application of pesticides and fertilizers have been an inevitable agricultural production issue in various countries around the world. New technologies and policies are constantly trying to improve their application efficiency. This paper utilizes panel data of the provincial level in China from 2009 to 2019 to empirically study the effect of green finance reform policies on the chemical fertilizer application intensity (FAI) and pesticide application intensity (PAI). Standard difference-in-differences (DID), synthetic DID, difference-in-difference-in differences (DDD), and spatial DID models are constructed for specific empirical analysis. The findings can be concluded as follows: (1) A unit of the green finance reform policy reduces FAI by 0.0144 and PAI by 1.7921 by promoting green technology innovation. (2) Government financial extractive capacity hinders the reduction effect of green finance on PAI. (3) Coastal geographical location is conducive to reducing PAI through green finance reform. (4) FAI and PAI show positive spatial autocorrelations, and the influence of green finance reform overflows to surrounding areas. The research results can provide policy references for countries around the world to promote the green development of agriculture and reduce environmental pollution.

The environmental impact assessment of China's ecological migration from a social-ecological perspective.

When accounting for the social-ecological impact of an ecological restoration program, both objective environmental contexts and people's subjective perceptions are required. While this kind of environmental impact assessment lacks a comprehensive perspective. We use the difference-in-differences model to evaluate the effect of the greenness of the landscape after ecological migration in the Qilian Mountains in China; and analysis of variance and fixed effects models are used to evaluate the effects of such ecological restoration programs on local people's perceptions. The results show that the ecological migration program in the Qilian Mountains has been successful at not only significantly improving remotely sensed greenness at the landscape scale, but also at enhancing immigrants' environmental perceptions. These findings demonstrate the environmental impacts of ecological migration from a social-ecological perspective, and can provide methodological implications for landscape planning to support a better understanding of ecological restoration programs in the drylands.

Has environmental protection tax reform promoted green transformation of enterprises? Evidence from China.

Facing the increasingly stringent constraints of resources and the environment, the green transformation of enterprises is imperative. This study selects A-share listed companies in Shanghai and Shenzhen from 2014 to 2021 as samples, using the difference-in-differences method to examine the impact of the environmental protection tax reform (EPTR) on the green transformation of enterprises. The results indicate that the EPTR can promote the green transformation of enterprises, achieving this through three channels: raising the cost of pollution, strengthening the rigidity of law enforcement, and breaking the collusion between the government and enterprises. Notably, this promotional effect is more significant in non-state-owned enterprises, companies in the eastern and western regions, firms with low financing constraints, and those with high media attention. Further analysis shows that the EPTR has a positive impact on the green total factor productivity (GTFP) of enterprises, which implies that enterprises are not only proactively pushing for a green transformation at the strategic level but also taking practical actions. This study responds to the problem of the greening of tax system to promote the green development of enterprises from two aspects of enterprise strategic implementation and productivity and explores the impact mechanism from the perspective of institutional logic. It enriches the research on the effectiveness of the EPTR at the micro-level and broadens the research perspective on the impact mechanisms of environmental regulation. The findings of this study provide references for further optimising relevant policies and regulations and also offer insights for other countries and regions seeking sustainable development.

Impact of Environmental Protection Tax on carbon intensity in China.

In the context of increasingly severe global climate change, finding effective carbon emission reduction strategies has become key to mitigating climate change. Environmental Protection Tax (EPT), as a widely recognized method, effectively promotes climate change mitigation by encouraging emission reduction behaviors and promoting the application of clean technologies. Based on data from 282 cities in China, this paper takes the official implementation of the EPT in 2018 as the policy impact and the cities with increased tax rates for air taxable pollutants as the treatment group and uses DID model to systematically demonstrate the relationship between the implementation of the EPT and carbon intensity (CI) and further explores the possible pollutant emissions and green innovation mediating effects. The findings show that (1) the implementation of EPT can effectively reduce CI by about 4.75%, and this conclusion still holds after considering the robustness of variable selection bias, elimination of other normal effects, policy setting time bias, and self-selection bias. (2) The implementation of EPT can reduce CI by reducing pollutant emissions and improving the level of green innovation. (3) There is obvious regional heterogeneity in the carbon reduction effect of EPT, and the implementation of EPT has a more significant effect on CI in medium-tax areas, low environmental concern areas, general cities, and eastern regions. This paper not only provides a new analytical perspective for systematically understanding the carbon emission reduction effect of EPT but also provides policy insights for promoting regional green transformation and advancing carbon peak carbon neutralization.

Can carbon emission trading improve regional eco-efficiency? Based on the environmental innovation perspective.

This paper uses green innovation and environmental pollution as the mediating variables to construct a mediating effect model to investigate whether China's carbon emission trading policy can improve regional eco-efficiency by reducing regional environmental pollution and stimulating green innovation. This study is based on panel data from 30 provinces and municipalities directly under China's central government and autonomous regions from 2003 to 2019. The eco-efficiency of these provinces is measured using the super-efficiency DEA model and the difference-in-difference method (DID). The results show that (1) China's emission trading policy significantly improves regional ecological efficiency and the per capita GDP. The improvement can effectively improve regional ecological efficiency. (2) The mediating effect of green innovation and environmental pollution is significant. That is, China's carbon emission trading policy further improves regional ecological efficiency by stimulating more green innovation and reducing the synergy brought by environmental pollution. (3) There are differences in the feedback of this impact mechanism between different regions: It shows the characteristics of the western region being more significant than the eastern region. The central region has no significant effect. The research conclusion can provide a policy reference for the subsequent unified promotion of the construction of a carbon emission trading market nationwide and a theoretical basis for helping to achieve the "dual carbon" goal.

Contagion to unrest: Investigating the link between disease and civil unrest in Africa.

Scholars, policymakers, and citizens alike remain invested in the impact of infectious diseases worldwide. Studies have found that emerging diseases and disease outbreaks burden global economies and public health goals. This article explores the potential link between measles outbreaks and various forms of civil unrest, such as demonstrations, riots, strikes, and other anti-government violence, in four central African countries from 1996 to 2005. Using a difference-in-differences model, we examine whether disease outbreaks have a discernible impact on the prevalence of civil unrest. While our findings indicate that the relationship between disease and civil unrest is not as strong as previously suggested, we identify a notable trend that warrants further investigation. These results have significant implications for health and policy officials in understanding the complex interplay between state fragility, civil unrest, and the spread of disease.

Impact of multiple sclerosis on employment and income: Insights from a random sample representative of private sector employees in France using longitudinal administrative data.

In France, few data sources are available to estimate the impact of multiple sclerosis (MS) on job retention and its consequences on the level of resources, especially in large representative samples. The aim of the present study was to measure impact of MS on employment rates, wages and income (including unemployment benefit, sickness benefit and disability pension) by comparing work trajectories of people living with MS with those of a matched control group. We used the HYGIE database, which is the result of the linkage of two administrative databases in the private sector for a random sample of over 900,000 people. In order to identify the causal effect of MS on employment after 1 to 20 years, the difference-in-differences method with matching (age, sex, career and health history) was used, overall and in subgroups. The year of entry in long-term disease status for MS was used to approximate the onset of MS. Overall, 946 people with MS were included. Their situation was fairly favorable before MS (88.1% in employment, resources higher than the median for the general population), but MS had strong and continuous negative effects. Indeed, at 10 years, the employment rate fell by 28.6 percentage points (pp) and the disability pension allowance increased by 50.5 pp; the wage percentile fell by 19.2 pp and the replacement income accounted for a growing share of total income (+ 39.7 pp). Although administrative data had several strengths, clinical information on the severity of the disease or on its therapeutic management was not available. In conclusion, this study shows that the effects of MS on the employed population in the private sector occur early in the disease course and are cumulative, and that replacement income helps to reduce the loss of resources thanks to the French health and social system.

Chronic health conditions and their impact on the labor market. A cross-country comparison in Europe.

Objectives: To estimate the effect of having a chronic disease on the weekly working hours and the associated monetary losses. Design: Longitudinal data Survey of Health, Aging and Retirement (SHARE) in Europe. We analyzed 7 waves from 9 countries in Europe. A total of 80.672 observations. Setting: Participants who have their regular domicile in the respective SHARE country were interviewed face-to-face. Participants: Data from individuals aged between 50 and 65 years old in European countries were collected over seven years. A person was excluded from the survey if incarcerated, hospitalized or out of the country during the entire survey period, unable to speak the country's language(s) or moved to an unknown address. Interventions: Not applicable. Main outcome measurements: We applied a difference-in-differences with multiple time periods approach to estimate the effect of having a chronic condition on the number of working hours per week. We monetized the estimated productivity losses using the legal minimum wage in each country. Results: Persons with a chronic condition consistently reduced their weekly working hours compared to their healthy counterparts in the same country. This effect was more pronounced for men (6,78 hours per week or 352 hours per year) than women (3,97 hours per week or 206 hours per year). Persons with stroke, vascular, and lung disease showed the highest impact. On average, the reduced working hours represent about USD 12,80 billion annually in productivity losses in our sample. Conclusion: Having a chronic condition leads to people decreasing their working hours, which has significant economic losses. More severe health conditions showed the highest effects. This trend is observed in all the analyzed countries, highlighting the relevance of health and social systems to go beyond mortality and morbidity and the need to incorporate functioning in their target goals.

Can family doctor system improve health service utilization for patients with hypertension and diabetes in China? A difference-in-differences study.

BACKGROUND: Family doctors, serving as gatekeepers, are the core of primary health care to meet basic health needs, provide accessible care, and improve attainable health. The study objective was to evaluate the impact of the family doctor system on health service utilization among patients with hypertension and diabetes in China. METHODS: Difference-in-Differences (DID) models are constructed to estimate the net effect of the family doctor system, based on the official health management records and medical insurance claim data of patients with hypertension and diabetes in an eastern city of China. RESULTS: The family doctor system significantly increases follow-up visits (hypertension patients coef. = 0.13, diabetes patients coef. = 0.08, both p < 0.001) and outpatient visits (hypertension patients coef. = 0.08, diabetes patients coef. = 0.05, both p < 0.001) among the contracted compared to the non-contracted. The proportion of outpatient visits in community health centers among the contracted significantly rose (hypertension patients coef. = 0.02, diabetes patients coef. = 0.04, both p < 0.001) due to significantly more outpatient visits in community health centers and fewer in secondary and tertiary hospitals. It also significantly mitigates the increase in inpatient admissions among hypertension patients but not among diabetes patients. CONCLUSIONS: The examined family doctor system strengthens primary care, both by increasing follow-up visits and outpatient visits and promoting a rationalized structure of outpatient utilization in China.

Impact assessment of mandatory safety device installation for gas stoves.

Numerous fire accidents have occurred in Japan owing to food overheating when cooking on gas stoves because users left the cooking area unattended. In response, authorities enacted a legal revision mandating temperature sensor installation on gas stove burners. Nevertheless, the actual effectiveness of this measure remains uncertain. Furthermore, prior studies have raised concerns about the efficacy of specific safety standards for consumer products owing to insufficient evidence of reduction in accidents. Consequently, this study seeks to assess the impact of the standards revision implemented in 2008, requiring the placement of safety devices on all gas stove burners. Through a comprehensive analysis, it was aimed to ascertain how these measures have precisely influenced safety outcomes in cooking-related incidents. The data in this study were subdivided to mitigate potential bias from user attributes during data collection. The analysis employed the difference-in-differences method, specifically utilizing one-burner gas stoves unaffected by the standards revision. The data used in this study include accidents associated with gas stoves, spanning the period 2007-2019. To estimate the likelihood of overheating accidents, a binomial distribution model that utilized the Markov chain Monte Carlo methods was applied. For gas stoves with two or more burners, which were affected by the standards revision, the estimated probability of overheating accidents decreased by approximately 80%. In contrast, no decreasing trend was observed for one-burner gas stoves. The analysis suggests that the mandatory installation of safety devices on gas stoves has indeed resulted in a significant reduction in overheating accidents.

The impact of the energy-consuming right trading system on corporate environmental performance: Based on empirical evidence from panel data of industrial enterprises listed in pilot regions.

The energy-consuming right trading system (ECRTS) is a significant institutional innovation in China to address the increasingly severe energy crisis and environmental issues. Identifying the policy effects of energy consumption rights on corporate environmental performance (CEP) is conducive to achieving a win-win situation for China's economic growth and carbon neutrality. This study aims to analyze the impact of energy-consuming right trading system on corporate environmental performance and provide empirical evidence and policy implications for the full implementation of future policies. Using data from Chinese listed industrial enterprises from 2012 to 2019 and adopting the difference-in-differences method and mediation analysis, we empirically analyze the policy effects of energy-consuming right trading system. We find that the energy-consuming right trading system significantly promotes the improvement of corporate environmental performance, and the conclusion remains valid after a series of robustness tests. Further mechanism examinations indicate that the system mainly enhances environmental performance by affecting corporate green technological innovation. Heterogeneity tests suggest that the energy-consuming right trading system has a stronger impact on companies in economically developed regions, non-state-owned enterprises, and those with higher asset flexibility. Our research results can aid in the green transformation of enterprises and provide practical evidence for China to accelerate the comprehensive construction of the energy consumption rights trading market.

Post-traumatic growth in later-life cognitive function? Evidence from the 1976 Great Tangshan Earthquake.

OBJECTIVES: This study aimed to explore the long-term impacts of exposure to earthquake in adolescence on later-life cognitive function in China. METHODS: Data were from the 2015 China Health and Retirement Longitudinal Study (CHARLS). Our analytical sample comprised 4394 participants aged 49 to 78 from two birth cohorts born between 1937 and 1966: exposed cohort during adolescence (born between 1952 and 1966), and non-exposed cohort during adolescence (born between 1937 and 1951). We defined earthquake exposure as the exposure severity of the 1976 Great Tangshan Earthquake (GTE). We selected community environmental characteristics as our key moderators. A difference-in-differences (DID) method was employed to estimate the long-term impact of the GTE on later-life cognitive function. RESULTS: We found that exposure to the earthquake during adolescence resulted in higher scores of later-life cognitive function (for males: ß = 2.18; 95% CI: 0.70-3.66; for females: ß = 1.22; 95% CI: 0.11-2.33). For males, this impact was moderated by community environmental characteristics including the old-age allowance program (ß = 3.07; 95% CI: 1.94-4.19) and the condition of basic community infrastructures (ß = 1.52; 95% CI: 0.84-2.19). CONCLUSIONS: Our study supports the post-traumatic growth theory. This finding suggest that individuals with early-life traumatic exposure need to be focused on. Additionally, improving the conditions of community infrastructures and establishing a community environment with comfort and security may be pretty important for promoting cognitive function and post-traumatic growth.

Effective policy research of county and township health sector integration in China: Empirical evidence from the difference-in-differences model.

Medical service fragmentation is a common problem worldwide, and many countries have adopted integration to solve the difficulty. Contrary to developed countries, developing countries such as China must consider how to implement integration under a relatively weak medical foundation. This study aims to evaluate the effect of the "Compact Union of County and Township Health Sectors" policy on the medical service capacity of a typical integration model represented by Shanxi Province in China and determine the path the policy followed. By using Shanxi's county-level medical integration as a quasi-natural experiment, this study establishes a difference-in-differences model to investigate the effect of the policy using official data. A series of tests are conducted to verify the robustness of the result. Finally, the policy pathway is tested. The results show that the third-level surgeries and outpatient service utilization of leading hospitals and township institutions increased. Still, inpatient service utilization and fourth-level surgeries did not show a significant change in either type of institution. Moreover, the enhancement of leading hospitals' service capacity comes mainly through improving asset efficiency and personal income, while the improvement of township institutions' capacity comes primarily through increased personal income. Compact integration of county-level medical institutions can stimulate and improve service capacity by improving asset efficiency and personal income, even with a weak medical foundation. However, to achieve continuous service capacity improvement, the professional level of county-level institutions must be strengthened with a superior hospital's assistance, and personnel's enthusiasm for active innovation must be cultivated.

Effect of extreme high temperature on cognitive function at different time scales: A national difference-in-differences analysis.

BACKGROUND: Mounting evidence has demonstrated that high temperature was associated with adverse health outcomes, especially morbidity and mortality. Nonetheless, the impact of extreme high temperature on cognitive performance, which is the fundamental capacity for interpreting one's surroundings, decision-making, and acquiring new abilities, has not been thoroughly investigated. METHODS: We aimed to assess associations between extreme high temperature at different time scales and poor cognitive function. We used longitudinal survey data from the three waves of data from China Family Panel Study, providing an 8-year follow-up of 53,008 participants from China. We assessed temperature and extreme high temperature exposure for each participant based on the residential area and date of cognitive test. We defined the proportion of days/hours above 32 °C as the metric of the exposure to extreme high temperature. Then we used generalized additive model and difference-in-differences approach to explore the associations between extreme high temperature and cognitive function. RESULTS: Our results demonstrated that either acute exposure or long-term exposure to extreme high temperature was associated with cognitive decline. At hourly level, 0-1 hour acute exposure to extreme high temperature would induce -0.93 % (95 % CI: -1.46 %, -0.39 %) cognitive change. At annual level, 10 percentage point increase in the hours proportion exceeding 32 °C in the past two years induced -9.87 % (95 % CI: -13.99 %, -5.75 %) cognitive change. Furthermore, subgroup analyses indicated adaptation effect: for the same 10 percentage increase in hours proportion exceeding 32 °C, people in warmer areas had cognitive change of -6.41 % (-11.22 %, -1.61 %), compared with -15.30 % (-21.07 %, -9.53 %) for people in cool areas. CONCLUSION: Our results demonstrated that extreme high temperature was associated with reduced cognitive function at hourly, daily and annual levels, warning that people should take better measures to protect the cognitive function in the context of climate change.

Relationships between long-term exposure to major PM2.5 constituents and outpatient visits and hospitalizations in Guangdong, China.

Ambient fine particulate matter (PM2.5) has attracted considerable attention due to its crucial role in the rising global disease burden. Evidence of health risks associated with exposure to PM2.5 and its major constituents is important for advancing hazard assessments and air pollution emission policies. We investigated the relationship between exposure to major constituents of PM2.5 and outpatient visits as well as hospitalizations in Guangdong Province, China, where 127 million residents live in a severe PM2.5 pollution environment. An approach that integrates the generalized weighted quantile sum (gWQS) regression with the difference-in-differences (DID) approach was used to assess the overall mixture effects and relative contributions of each constituent. We observed significant associations between long-term exposure to the mixture of PM2.5 constituents (WQS index) and outpatient visits (IR%, percentage increases in risk per unit WQS index increase:1.73, 95%CI: 1.72, 1.74) as well as hospitalizations (IR%:5.15, 95%CI: 5.11, 5.20). Black carbon (weight: 0.34) and nitrate (weight: 0.60) respectively exhibited the highest contributions to outpatient visits and hospitalizations. The overall mixture effects on outpatient visits and hospitalizations were higher with increased summer air temperatures (IR%: 7.54, 95%CI: 7.33, 7.74 and IR%: 9.55, 95%CI: 8.36, 10.75, respectively) or decreased winter air temperatures (IR%: 1.88, 95%CI: 1.68, 2.08 and IR%: 4.87, 95%CI: 3.73, 6.02, respectively). Furthermore, the overall mixture effects on outpatient visits and hospitalizations were significantly higher in populations with higher socioeconomic status (P < 0.01). It's crucial to address the primary sources of nitrate precursor substances and black carbon (mainly traffic-related and industrial-related air pollutants) and consider the complex interaction effects between air temperature and PM2.5 in the context of climate change. Of particular concern is the need to prioritize healthcare demands in economically disadvantaged regions and to address the health inequalities stemming from the uneven distribution of healthcare resources and PM2.5 pollution.

Research on the impact of the national ecological demonstration zone on green total factor productivity: Evidence from China.

China is currently confronted with the dilemma of achieving its green development goals while maintaining economic growth. The National Ecological Demonstration Zones (NEDZs) represent an innovative attempt by local governments to balance economic development with ecological civilisation, potentially offering a solution to this issue. This study calculated the Green Total Factor Productivity (GTFP) for 1925 districts and counties from 1999 to 2018. Using the selection of NEDZs as a quasi-natural experiment, a difference-in-differences model was employed to empirically analyse the impact of NEDZs on GTFP. The results indicated that the establishment of NEDZs led to an average increase in GTFP of 0.2175 compared to the control group. The primary mechanisms involved are innovation, structure, and enforcement. Moreover, the green development effects of the NEDZs exhibited regional heterogeneity. Compared to the western regions, the central and eastern regions showed limited green development effects. Areas with smaller populations, lower human capital, and lower administrative levels demonstrated significant improvements after the implementation of the NEDZ. Further analysis reveals a significant spatial agglomeration pattern of GTFP and the NEDZs exert a strong 'siphon effect' on the GTFP of neighbouring areas. This study provides a new perspective on the GTFP research and offers theoretical and practical evidence for assessing the impact of NEDZs.

Farmland protection and fertilization intensity: Empirical evidence from preservation policy of Heilongjiang's black soil.

The preservation of cultivated land quality stands as a vital prerequisite for ensuring food security and sustainability. In the black soil area of northeast China, a large amount of fertilizer was used to stabilize grain production in its early stages, which damaged soil structure and polluted the ecological environment. Based on the panel data of fertilization intensity of 48 districts and counties in Heilongjiang Province from 2010 to 2020, this study takes the implementation of the "Three-Year Action Plan for the Protection of Black Soil Farmland in Heilongjiang Province for the (2018-2020)" (TYAP) policy as a natural experiment, and uses the difference-in-differences (DiD) method to identify the causal effect of the policy on the local fertilization intensity. The results of the empirical study showed that the implementation of the TYAP policy significantly reduced the fertilization intensity of the black soil cultivated land implemented by the policy during the implementation period, which resulted in a decrease of 11.97% on average compared with the areas without the policy implementation. Several robustness tests provided additional confirmation of the aforementioned findings. This study further revealed that the policy mitigated fertilization intensity by fostering advancements in agricultural mechanization.

Spatial difference-in-differences analysis of smart city pilot policy and industrial pollution reduction: the mediating role of S&T fiscal expenditure.

Smart city has become one of the most important tool to achieve digital transformation and intelligent development. However, the impacts of smart city pilots (SCP) on different industrial pollution have yet to be tested, and the mechanisms of SCP affect industrial pollution could be richer. In this paper, we construct a spatial difference-in-difference model for 2004-2019 by mapping SCP policy to Chinese city data to systematically quantify the impact and its potential mechanisms of digital transformation on industrial pollution. Our results show that the SCP policy achieves industrial pollution reduction targets, on average, wastewater and SO2 emissions decreased by 6.4% and 6.5%, respectively. Cities with SCP policy have more industrial pollution compared to cities without SCP policy, implying a beggar-thy-neighbor effect of SCP policy. Furthermore, significant regional disparities come to light; SCP policy in the Pearl River Delta exceeds other regions such as the Yangtze River Delta and Jing-Jin-Ji city cluster in terms of realizing the impact of industrial pollution reduction. Importantly, mechanism analysis indicated that the SCP reduced industrial pollution was partially mediated by government S&T fiscal expenditure.

Effect of marine ecological compensation policy on coastal water pollution: Evidence from China based on a multiple period difference-in-differences approach.

With the development and utilization of marine resources, coastal water pollution has become increasingly prominent. The marine ecological compensation (MEC) is a key measure to balance the utilization of marine resources and the protection of marine environment. This paper attempts to explore the governance effect of MEC policy on coastal water pollution. Based on panel data of coastal cities in China from 2006 to 2020, a multiple period difference-in-differences (DID) model is used to estimate the impact of MEC policy on coastal water pollution. The research results show that the coastal water pollution has decreased significantly in the polit cities after implementing the MEC policy. The governance effect of MEC policy on coastal water pollution will last for three year and cover areas within a geographical distance of 200 km. The transmission mechanisms of MEC policy on coastal water pollution are the reduction of land-based sewage, marine technological progress and optimization of industrial structure. Further, this paper provides operational suggestions for strengthening the governance effect of MEC policy on coastal water pollution.