The Impact of Mandatory Environmental Information Disclosure and the Green Innovation of Pollution-Intensive Companies? Evidence From China

Based on the Guidelines of the Shanghai Stock Exchange on Environmental Information Disclosure for Listed Companies issued in 2008, this paper constructs a quasi-natural experiment and uses the did method to study the impact of mandatory environmental information disclosure on the green innovation of pollution-intensive companies in China. The results show that mandatory environmental information disclosure can signicantly promote the green innovation of pollution-intensive companies by strengthening the company's motivation and pressure to comply with the regulation; in addition, the positive effect is more obvious in state-owned companies, small companies and companies with poor information condition in pollution-intensive industries. This paper enriches the literature of mandatory environmental information disclosure and offers guidance for policymakers seeking to improve environmental information disclosure policies in emerging countries.


Introduction
Since the reform and opening up for 40 years, China's economy has made remarkable achievements, and companies have also made great progress in transforming the traditional pattern of economic growth.
However, the extensive economic growth mode is still obvious, which brings serious ecological and environmental problems. As the main producers of pollution, many companies just focus on short-term interests, blindly pursue the maximization of interests. The lack of environmental responsibility has seriously affected the life of people, and restricted the sustainable development of China's economy. In order to urge companies to ful ll their environmental responsibilities, the Chinese government has issued a series of laws and regulations in recent years. However, due to the different interest between the central and local governments, these policies have not achieved the expected effect and the proportion and quality of corporate environmental information disclosure is still poor. Control environmental pollution has become an important prerequisite for the sustainable development of China. In this context, the Shanghai Stock Exchange issued the guidelines on environmental information disclosure of listed companies on the Shanghai Stock Exchange (Guideline hereafter) in 2008, which requires companies listed in Shanghai Stock Exchange to disclose their environmental information.
Company transform through green innovation is an important way for the long-term economic development of the country, and also an effective way to promote the green development of the company. (Xiong et al. 2020)According to the institutional theory, the original driver of corporate innovation is institutional pressure (Bansal 2005), such as environmental regulation implemented by the government. As an important part of environmental regulation, although the mandatory environmental information disclosure (MEID hereafter) has been implemented in China for a period of time, can it promote the innovation of companies? It's still not clear. At present, there are two different views on the advantages and disadvantages of environmental information disclosure. On the one hand, based on the signaling theory, environmental information disclosure can alleviate the information asymmetry of companies (He et al. 2012), improve the social reputation of companies, and companies can obtain more nancing opportunities and improve their economic performance (Li et al. 2013). On the other hand, based on the agency theory, environmental information disclosure is the self-interest behavior of management to cover up the negative news of companies (Tian &Wang 2017). There are few literatures on the effectiveness of MEID from the perspective of corporate innovation. In addition, the extant articles mainly focus on the developed countries, such as the United States, less in the context of developing countries. In order to ll the above gaps, this paper studies the impact of MEID on corporate green innovation in the largest developing country, China.
In this paper, we aim to address the following two questions: will the MEID promote or hamper the green innovation of pollution-intensive companies? What factors affect the effect of MEID on corporate green innovation? Our sample are the companies in pollution-intensive industries listed on the A-shares of the Shanghai Stock Exchange and Shenzhen Stock Exchange between 2007and 2016. Speci cally, we use the pollution-intensive companies listed in the Shanghai Stock Exchange as the treatment group while those listed on the Shenzhen Stock Exchange, which are not subject to similar disclosure regulations, as the control group. Employing a did model, we examine the impact of MEID on corporate green innovation based on manually collected patent data. The results show that: MEID signi cantly promote the green innovation of pollution-intensive companies; in addition, the positive impact of mandatory environmental information disclosure is more obvious in the poor information environment, state-owned companies and small companies in pollution-intensive industries. We also conduct various supplementary analyses to show our results are robust.
Our study makes several contributions to the literature. First, this paper focuses on the impact of MEID on pollution-intensive corporate innovation, provides empirical evidence for the effectiveness of MEID, and enriches the research on the MEID policy; Second, the extant literatures on the in uence factors of corporate green innovation pay less attention to the mandatory environmental information disclosure. This paper explores the impact of MEID on corporate green innovation on the base of the implementation of the Guidelines, provides a new perspective for the research on the in uence factors of corporate innovation; Third, this paper studies the heterogeneity of the impact of MEID from the aspects of information environment, property nature and company scale, which has a guidance for China and other countries to improve the environmental regulation to promote green innovation of different companies and protect environment; Fourthly, this paper takes China as the background to ll the gap that previous literatures mainly focus on the United States and other developed countries but lack of evidence from developing countries.
The reminder of this paper is arranged as follows. Section 2.1 looks at the institutional setting, Sect. 2.2 offers the literature reviews, followed by the research hypothesis in Sect. 2.3 ; Sect. 3 presents the research design, and describes the data and methods used in the paper; Sect. 4, tests the impact of MEID on the green innovation of pollution-intensive companies; then, analyzes the impact of MEID on the green innovation of pollution-intensive companies in the good information environment and the poor information environment, state-owned companies. Section5 is the robustness test. Conclusion and discussion are given in Sect. 6.

Institutional background
Since the 1970s, China has promulgated a series of environmental protection laws and regulations, such as the environmental protection law of the people's Republic of China, in which there are few provisions on company environmental information disclosure. Until the beginning of this century, the Chinese government began to pay attention to the environmental information disclosure of listed companies. In 2001, the former State Environmental Protection Administration issued the Notice on environmental protection inspection of listed companies, which encouraged listed companies to actively disclose environmental information. In 2007, China issued the document Environmental Information Disclosure Measures, which is the rst department regulation of environmental information disclosure. However, at that time, the environmental information disclosure was mainly voluntary, and the disclosure level was poor, which created opportunities for companies to hide environmental pollution information and increased the cost of government supervision.
With the increasing attention to economic and environmental sustainability in the world, companies are required to pay more attention to their environmental social responsibility. In China, the lack of environmental social responsibility has become a shocking problem . In order to cope with the public concern about environmental problems, the Chinese government has taken many measures to encourage companies to undertake their responsibility. For example, 1. China's Company Law 2006 requires companies to undertake social responsibility in the process of practical work; 2. The Green Credit Guide issued by China Banking Regulatory Commission links bank nancing with CSR performance of companies; 3. Establish the blacklist of Environmental Protection Bureau in China's Ministry of environmental protection, and blacklist the companies with serious pollution ; 4. Use newspapers and other media to award a honorary titles to the companies that actively perform social responsibility. In addition, in order to ensure the openness and transparency of companies' environmental social responsibility, the Shanghai Stock Exchange issued the Guidelines on Environmental Information Disclosure of Listed Companies in Shanghai Stock Exchange in 2008, which requires all companies listed on the Shanghai Stock Exchange to disclose environmental information in their reports, including quantitative indicators such as environmental protection investment, technology development and environmental protection performance, as well as the information of the national standards, historical situation, environmental levels between industries and other aspects of the detailed requirements.
Due to the external nature of the MEID policy for a single company, we use the policy issued by Shanghai Stock Exchange in 2008 as a quasi-natural experiment to test the green innovation of experimental companies (mandatory environmental information disclosure companies) and control companies (other companies) before and after the policy.

Literature review
China has experienced impressive economic growth since the economic reforms in the late 1970s. To speed up industrialization, economic development was prioritized, with all related social and environmental issues being pushed back. Ip (2009) describes the essence of Deng Xiaoping's economic reform in the 1990s as the 'culture of pro t', where to pursue pro t at any cost. Such a philosophy has inevitably caused unbalanced growth in China, resulting in signi cant social and environmental costs (Kolk et al. 2009). A heavily polluted environment has become alarming issues, which may even further threaten social stability, and companies are the main producers of environmental pollution. In this case, the Shanghai Stock Exchange issued a policy in 2008, requiring all pollution intensive companies listed here to release environmental information.
At present, scholars have carried out an intense discussion on the advantages and disadvantages of environmental information disclosure. Based on the signaling theory, some scholars believe that shareholders, investors and other stakeholders regard corporate environmental behavior as an indicator of risk management and nancial responsibility, and environmental information disclosure can increase the transparency of companies in environmental protection, thus affecting their behavioral decisionmaking (Hamilton 1995). Inoue (2016) found that environmental information disclosure can improve the communication between companies and other stakeholders, stimulate companies to expand the scope of information disclosure, and increase their innovation activities. Plumlee et al. (2015) found that the quality of environmental information disclosure helps to enhance value of companies by improving the cash ow and reducing the cost of equity capital. They believe that environmental information disclosure can creating indispensable conditions for companies to implement innovation strategy by improving the legitimacy of companies, passing information and enhancing the understanding, support and trust of stakeholders(Zhao &Meng 2016). Balla et al. (2018) studied the relationship between the legitimacy of environmental protection agencies and ecological innovation in the UK and Ireland, emphasizing that environmental protection agencies use incentive schemes and voluntary agreements to establish a trust relationship with regulated companies, so as to promote ecological innovation.
Other scholars hold different opinions. On the one hand, from the perspective of management selfinterest, they believe that when the company discloses environmental information, managers may choose to provide private interests rather than social interests of corporate environmental social responsibility activities (Friedman 1970). In addition, environmental information disclosure also has the negative effect of improving the degree of information asymmetry. Corporate social responsibility information disclosure will divert the attention of information users to cover up negative information such as poor nancial performance (Hemingway &Maclagan 2004). Taking A-share listed companies from 2008 to 2012 as samples, Quan et al. (2015) found that the disclosure of social responsibility information reduced the information transparency and increased the property hoarding of manager. On the other hand, they believe that the goal of the company is to create pro ts, so any activity to ful ll corporate social responsibility is an obstacle to achieve the goal of maximizing pro ts. Ren et al. (2020) found that environmental information disclosure will consume limited resources of companies, which will have a negative impact on the economic performance. However, Marshall et al showed that the relationship between environmental information disclosure and company value is not signi cant (Marshall et al. 2009). Therefore, if environmental information disclosure can increase information transparency and alleviate the problem of information asymmetry, MEID could also drive corporate innovation as an important environmental regulatory tool of information disclosure(Wang &Ning 2020). Yu et al. (2019) found that environmental regulation, taking environmental law enforcement and supervision as an example, drives the green transformation of company by increasing emission costs, reducing company operation e ciency and increasing punishment. Wang and Ning also support that mandatory social responsibility disclosure can drive company transformation. By studying resource-based companies in China, Li et al. (2020) found that environmental regulation can improve technological innovation of these companies.
The research of Zhang and Ge suggest that the innovation level of companies undertaking the obligation of MEID has been signi cantly improved (Zhang &Ge 2021). On the contrary, if environmental information disclosure increases the degree of information asymmetry of company, then MEID cannot be regarded as an appropriate, strict and effective environmental regulation policy, so it cannot drive company innovation (Porter &Linda 1995).
In general, the extant research on the economic consequences of environmental information disclosure is scattered and uncoordinated. In addition, most of the existing research is from a macro perspective, and the research about the impact of MEID on green innovation is scarce, especially in developing countries.
As an important part of environmental regulation, whether the MEID can drive the green innovation of pollution-intensive companies is not only related to the transformation of companies, but also helps to provide guidance for solving ecological problems, protecting environment and achieving sustainability. It is of great signi cance to study the impact of MEID on corporate green innovation.

Hypothesis development
Companies is becoming the main maker of environmental pollution in China. To achieve sustainable development of environment, the key lies in promoting green innovation of companies, improving their production mode and emission mode, and realizing the transformation of companies. However, due to the uncertainty and long cycle of company innovation, the ability and willingness of enterprises to carry out green innovation actively are often insu cient (Jin et al. 2019). MEID can increase the transparency of information, enable the government, investors and other stakeholders to supervise the environmental behavior of companies more easily. That is to say, the environmental information of companies is subject to the dual supervision of the government law enforcement departments and the capital market at the same time, which makes the environmental externality of companies internalized, and forces companies to change their environmental governance strategies, from passive governance to active innovation and transformation (Guo 2019). According to legitimacy theory, legitimacy is crucial to the survival and development of companies, because it enables the company to obtain the support of various stakeholders (such as suppliers, distributors, customers and the government), so ensures the continuous ow of external resources into the company. As the main producers of pollution, the legitimacy of companies will be questioned. Therefore, they have reason and motivation to take positive strategies to obtain legitimacy recognition (Shen et al. 2014). For this reason, in China, MEID promotes corporate green innovation through two way: On the one hand, MEID will affect corporate reputation and cost of capital, because this information will be concerned by investors in China's capital market. If company ca not abide by the contract with stakeholders, but cause serious environmental pollution to the society, stakeholders (including public) will try to protect their own living environment. For example, for companies with poor environmental performance, investors often "vote with their feet" to deal with the punishment and litigation risk brought by environmental pollution through risk premium or investment reduction, which makes companies face higher nancing cost (Doshi et al. 2013). Therefore, companies have the motivation to adopt a positive environmental governance strategy such as green innovation to prove the legitimacy of their business activities and obtain the trust of external stakeholders, so as to ensure that companies have su cient resources for development.
di cult to form new innovation products, because most of these are ine cient investments for the purpose of "tools", which wasting the resources to truly realize green innovation. Therefore, this paper proposes: Hypothyesis 1b. MEID cannot promote the green innovation of pollution-intensive companies.
The effect of MEID on company green innovation may be affected by the information condition of the company. When the company's information condition is poor, the degree of information asymmetry is high, so it is di cult for the market to supervise and guarantee the behavior related to environment of a company. In this case, the MEID can improve information transparency and form institutional pressure on enterprises. From the perspective of normative legitimacy, in order to respond to the external requirements of the environment protection, enterprises will be more motivated to take positive strategies. On the contrary, when the company information condition is better, its own behavior will be concerned by all walks of life. Therefore, the effect of using some mandatory policy to in uence enterprise will be weakened. Therefore, this paper proposes: Hypothyesis 2 Compared with the companies with better information condition, companies with poor information condition exhibit more increase in green innovation subsequent to the MEID.
The effect of MEID on corporate green innovation may be affected by the nature of property rights. At present, researches abroad and in China basically support a positive correlation between the nature of company ownership and environmental information disclosure. For example, Stephen (1998) studied 49 listed companies in Zimbabwe and found that ownership structure has a signi cant positive effect on MEID. From the perspective of Chinese situation, rst of all, state-owned companies often bear the goal of government utility. When they are required to disclose company environmental information, they feel more pressure and need to realize their commitment to corporate social responsibility. Secondly, the performance evaluation of the mangers in charge of the state-owned company is often linked with the implementation of national policies and social responsibility. At the same time, state-owned company's manger has their own pursuit of political interests, so they are more willing to take actions that meet the expectations of the government, such as ful lling their environmental and social responsibilities (Lu et al. 2012). Therefore, the driving effect of MEID on company green innovation is more obvious. By contrast, it's not necessary for private companies to pursue political connections, so they will not actively carry out green innovation when facing the requirements of MEID. Therefore, this paper proposes: Hypothyesis 3 Compared with non-state-owned companies, MEID has more obvious driving effect on green innovation of state-owned companies.
The effect of MEID on corporate green innovation may be affected by company scale. Based on the analysis of legitimacy theory, in the face of external pressure brought by compulsory environmental information disclosure, small companies will be more active in innovation than large enterprises with abundant resources. On the one hand, they need to obtain the recognition of government, so as to get the right to develop or use natural resources; on the other hand, active innovation for transformation can transmit positive information to the market, get the trust of investors by catering to the widely accepted values and ethics of the society, and reduce the cost of capital. In contrast, large companies have enough resources and development opportunities, they may not be able to take the initiative to carry out green innovation when facing the pressure of environmental regulation. Therefore, this paper proposes: Hypothyesis 4 Compared with large companies, the driving effect of MEID on green innovation is more obvious in small companies.

Materials And Methods
Sample and data sources For the identi cation of pollution intensive companies, referring to the classi cation in the second national pollution source survey plan of the State Council in 2017, this paper classi ed classi es 13 industries, including agricultural and sideline food processing industry, chemical raw materials and chemical products manufacturing industry, textile industry, automobile manufacturing industry, metal products industry, petroleum, coal and other fuel processing industry, ferrous metal smelting and rolling processing industry, and non-ferrous metal processing industry It belongs to 13 industries, including mining and dressing industry, non-ferrous metal smelting and rolling processing industry, electric power, heat production and supply industry, non-metallic mineral products industry, coal mining and washing industry, rubber and plastic products industry, which is de ned as pollution intensive industry. The data in this paper are mainly from Accounting Research (CSMAR) databases. To gain the list of companies with MEID, we collected according to the websites of Shanghai Stock Exchange and Shenzhen Stock Exchange manually. In addition, in order to avoid the impact of extreme value on the empirical results, this paper winsorizes all continuous variables at the top and bottom 1% of their distributions. Table 1 shows the distribution of samples by industry, in which the proportion of each industry in the treatment group and the control group is similar.  d.
Year is the annual dummy variable, and Industry is the industry dummy variable; e is the random error term.

Descriptive statistics
The descriptive statistical of the variables are presented in Table 2. In our sample, the mean of green innovation level (NEWP)is 1.617, the minimum of it is 0, the maximum of it is 8.915, the median of it is 1.386. There is a big difference between the minimum and the maximum, and the standard deviation is 1.735, which indicates that there is a certain difference in corporate green innovation. The mean of Treat is 0.625, which means 62.5% of companies require mandatory disclosure of environmental information; the mean of After is 0.8, which means that the sample after the implementation year accounts for 80% of the total sample. The standard deviation of the spatial dummy variable (Treat) and the temporal dummy variable (After) is less than 1.000, and the uctuation is small. In terms of control variables, except the standard deviation of Size is greater than 1.000, the standard deviations of other control variables are less than 1.000, and the uctuation is small. All variables are in a reasonable range.  Diff = the number of patents granted in the treatment group -the number of patents granted in the control group.
It can be seen that the green innovation level of the treatment group has improved after being required to disclose environmental information, which provides preliminary evidence for hypothesis 1.

Empirical regression results
Parallel trend is an important premise of double difference estimation. In this paper, parallel trend test is carried out rst. The results are shown in Fig. 1. Before the Guidelines was issued, the number of patent authorization maintained the same level and trend between the treatment group and the control group; After the implementation of the Guidelines in 2008, the trend showed changes, and the increase of the number of patents granted in the treatment group was higher than that in the control group obviously.
This result has passed the parallel trend test, which indicates that the did model is effective for this paper.
Based on the panel data of China's pollution intensive industries, this paper uses Stata 14.0 software to test the correlation among the variables of the (1) model. Table 4 reports the impact of mandatory environmental information disclosure on corporate green innovation. Without controlling other variables, the coe cient of the Treat *After is 0.241, which is signi cant at the 5% level; with controlling other variables, the coe cient of Treat * After is 0.223, which is also signi cant at the 5% level.  Robust standard errors in parentheses * p < 0.10, ** p < 0.05, *** p < 0.01 The above results show that for pollution-intensive companies, MEID and the number of the patents granted is positive correlated, and the degree of impact is not signi cant. That is to say, MEID signi cantly promotes the green innovation of pollution-intensive companies. As the theoretical analysis, because the mandatory environmental information disclosure improves the transparency of company information and increase the cost of company environmental violations, pollution-intensive companies will take the initiative to carry out innovation in order to obtain a good social reputation and obtain resources for company development. Thus, the results support Hypothesis 1a instead of Hypothesis 1b.

Information environment, MEID and corporate green innovation
The impact of MEID on corporate green innovation may be affected by the information condition (Follow). In order to verify whether there are differences of MEID on green innovation in different information environment conditions, this paper uses the natural logarithm of the sum of the number of analysts plus 1 to measure the quality of company information condition (Follow). Then, according to the quality of company information condition, the samples are divided into good information condition and bad information condition for grouping regression.
The results are shown in Table 5. Column (1) and Column (2) presents that the impacts of MEID on green innovation is different. The coe cient of Treat * After is signi cantly positive at the statistical level of 5% in the group with poor information condition, but not signi cant in the sample with better information condition. It means that, MEID has a more signi cant driving effect on the green innovation in pollutionintensive companies with poor information environment. This paper argues that, under the poor information condition, MEID can play a better role in easing the degree of information asymmetry, forming institutional pressure to promote green innovation of pollution-intensive companies. The results verify hypothesis 2.    The results of group regression are shown in Column (3) and Column (4) of Table 5. The results presents that the coe cient of Treat * After is positive in state-owned companies, and the signi cance is 10%, while in non-state-owned companies, the coe cient is positive, but not signi cant. Compared with nonstate-owned companies, MEID has a more signi cant driving effect on the green innovation of stateowned pollution-intensive companies.
This paper suggests that state-owned companies are generally required to bear more social responsibility (Yang &Qiao 2013), and the performance of social responsibility is often regarded as a part of the evaluation of state-owned company mangers. In addition, state-owned companies are easy to obtain government subsidies and loans, their funds and personnel are su cient. Therefore, under the pressure of the Guidelines, state-owned companies have more motivation and ability to carry out green innovation.
This results support hypothesis 3.

Scale, MEID and corporate green innovation
The impact of MEID on corporate green innovation may be affected by company size. In order to verify whether there are differences in the impact of MEID on company innovation under different company scale, the samples are divided into small companies and large companies.
The results are shown in Column (5) and Column (6) of Table 5. The results present that the coe cient of Treat * After of small companies is signi cantly positive at the level of 10%, which indicates that MEID can signi cantly promote the innovation of small pollution intensive companies; In contrast, the coe cient of Treat × After of large companies is positive, but not signi cant, which means that MEID cannot signi cantly promote the green innovation of large pollution intensive companies.
This shows that MEID can signi cantly drive the green innovation of small pollution-intensive companies.
Through the analysis of this paper, it is found that compared with large companies with su cient resources, small companies need to cater to the values and ethics of society for obtaining more resources and reducing the cost of capital for development. The results support Hypothesis 4.

PSM-DID
To reduce the differences between the treatment group and control group and highlight the effects of Guidelines, we use the propensity-score-matched (PSM) radius matching method to match the treatment group with the control group. The steps are as follows: rst, all the control variables are used as covariates to match the pollution intensive companies in Shanghai and Shenzhen stock markets. The nearest neighbor matching method is used to match the pollution intensive companies in Shanghai and Shenzhen stock markets. The matching ratio is 1:1, and the matched samples are retained; second, the DID model regression is performed on the matched samples. The test results are shown in column (1) of Table6. According to the results, MEID signi cantly promotes the green innovation of pollution-intensive companies, which is consistent with the research conclusion of this paper. Robust standard errors in parentheses * p < 0.10, ** p < 0.05, *** p < 0.01.
Using different methods to measure company innovation In the benchmark regression, we take the number of patents granted of listed companies as a proxy variable to measure the level of green innovation, and nd that MEID can promote the green innovation of pollution-intensive companies. Furthermore, the number of patents applications of listed companies is used to re measure the innovation level of companies. Results are shown in column (2) of Table 6. It can be seen that the coe cient of After * Treat is positive, and it is signi cant at the level of 10%, indicating that MEID can signi cantly promote corporate green innovation.

More control variable
This paper further controls other variables, including: the proportion of the largest shareholder (Top1), which is measured by the proportion of the largest shareholder; the size of the board of supervisors (inspect), which is measured by the natural logarithm of the number of supervisors (Yu et al. 2020). The results are shown in column (3) of Table 6, from which it shows that the coe cient of After * Treat is still signi cantly positive at the level of 5%. The result proves the robustness of the conclusion of this study once again.

Conclusion And Implications
Exploring the impact of MEID on the green innovation is of great practical signi cance to promote the capital market to support the construction of ecological civilization. Based on the quasi-natural event of the Guidelines, this paper takes pollution-intensive companies listed in Shanghai and Shenzhen A-shares from 2007 to 2016 as research samples, uses did method and manually collected patent data to test whether MEID can drive corporate green innovation. This study shows that there is a positive relationship between the MEID and the green innovation of pollution intensive companies because MEID can enhance the motivation and pressure of companies to comply with the regulation.
According, this paper concludes that: compared with companies that are not required to disclose environmental information, the MEID signi cantly promotes the green innovation of pollution-intensive companies that are required to disclose environmental information; The impact of MEID on the green innovation of pollution-intensive companies is heterogeneous in information environment, property nature and company scale. Speci cally, compared with the companies with better information environment, the role of MEID in promoting the green innovation of companies with poor information condition is more obvious; compared with non-state-owned companies, MEID can promote the green innovation of state-owned companies; MEID has a signi cant positive effect on the green innovation of small companies, but has a no effect in large-scale companies.
The conclusion is still robust after a series of robustness tests such as PSM-DID, changing the measure of corporate green innovation level and controlling more variables.
This paper enriches the research on the micro-economic consequences of MEID and the in uencing factors of corporate green innovation, provides some implication for policymakers in emerging countries that seek to improve environmental information disclouse. The implications are as follows: First, the government should continue to implement the MEID and improve the environmental monitoring system. Generally speaking, the obligation of environmental information disclosure helps to promote the green innovation of pollution-intensive companies, because mandatory environmental information disclosure can reduce the asymmetry of corporate environmental information, eliminate ine cient, outdated and polluting production mode through market competition mechanism. Effective information transmission can speed up the green innovation of companies. Therefore, from the perspective of the central government, we should further implement and improve environmental information disclosure to urge local companies to innovate effectively.
Second, the relevant departments should standardize the content of environmental information disclosure, increase audit efforts so as to improve the quality of environmental information disclosure.
The quality of environmental information disclosure is directly related to whether stakeholders can obtain real and su cient environmental information and make investment decisions consistent with expectations. At present, the disclosure level of qualitative information is higher than that of quantitative information, and the disclosure level of positive information is higher than that of negative information. This not only makes the environmental information disclosure a mere formality, but also increases the cost of company information disclosure, and increases the di culty and cost of government supervision.
Therefore, it is necessary for the relevant departments to standardize the content, form and evaluation standard of environmental information disclosure, form a uni ed environmental performance index, and increase the audit of information disclosure, so as to improve the e ciency of public supervision and reduce the cost of government supervision.
Third, the government should effectively identify the characteristics of the disclosure subject to formulate differentiated environmental information disclosure policy. Implementing environmental regulation blindly means not only high cost, but also low regulation e ciency. Therefore, it is necessary to combine the development stages of different industries and regions to avoid "one size ts all". For example, in the implementation of mandatory environmental information disclosure policy, we need to focus on guiding the companies with non-state-owned companies and large companies to promote their innovation through environmental information disclosure.
The possible de ciency of this paper is that it only measures the corporate green innovation from the number of patents granted or the proportion of patent applications. It does not construct a comprehensive index to measure the green innovation, which may ignore such factors as green innovation investment, green innovation e ciency and so on. We will further improve this problem in the future.