**5. Conclusions and Policy Recommendations**

This study applied panel ARDL and DEA simultaneously to assess economic growth and energy consumption in ecological disorder. Empirical results of panel ARDL confirm the inverted U-shaped EKC for these underline emerging countries as the GDP square's coefficient is significant with a negative sign. It implies that underlined countries expect to follow the EKC theory. Renewable energy also shows the negative sign for an ecological disorder, which implies that more renewable energy use can help to mitigate carbon emission. The indexes of energy efficiency, energy intensity, and environment show that underline countries suffer from environmental conditions due to high energy intensity and low energy efficiency. As economic growth demands more and more energy supply, renewable energy is the only source to meet this demand without compromising the environment. Thus, the conversion and trajectory of EKC heavily depend on energy consumption and energy sources. According to the results mentioned above, although EKC exists for underline developing economies, the trajectory of EKC has a question surrounding what and how this will happen. Therefore, it needs to be considered the other fundamentals (such as renewable or zero-carbon energy sources) to enhance the probability of EKC theory and speedup of its trajectory.

In the wake of the COVID-19 pandemic and global economic recessions, which resulted in a drastic drop in oil and other fossil fuel prices, green energy and energy efficiency projects are losing their economic feasibility. It will endanger the achievement of the Paris agreement goals on climate change and several sustainable development goals. Based on this study's results, the policy recommendations for the developing countries are to adopt new supportive policies for the development of green energy and energy efficiency projects. The emerging economies should endorse the development and transformation of low-carbon concepts and adopt a sustainable energy system. One of the significant obstacles to developing renewable energy and energy efficiency projects is their difficulties accessing finance. These projects are considered risky projects; hence, many financiers are reluctant to finance these projects [51,52]. Therefore, in the current and post- COVID-19 era, the necessity of employing green finance tools is highlighted [63].

Other actions can help to mitigate air pollution. For example, identifying and monitoring air pollution sources from industrial energy consumption, fuel supplies of regulating petroleum, and boosting vehicle sectors to adopt green fuels can substitute petroleum products. On the other hand, the reliance on renewable energy may enhance developing economies' growth and reduce the usage of fossil fuels. Diversification of the energy basket and relying more on renewable energy resources can also enhance energy security [51,52]. Simultaneously, increasing energy efficiency will be considered a cost-effective way to decrease energy production's environmental influences. Therefore, this study suggests that sustainable renewable energy production can be one of the main factors for sustainable development goals.

**Author Contributions:** Conceptualization, done by Q.A. and J.Z.; methodology, software form by M.M.; validation and formal analysis did by F.T.-H.; investigation, resources, data curation, performed by K.J.; writing—original draft preparation is done by M.A.; writing—review and editing and policy recommendations by W.L.; visualization, and supervision by M.A. All authors contributed equally to this paper. This research paper is contributed by the authors mentioned above in the following way. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Zhejiang province soft science project fund (2019C35019). Farhad Taghizadeh-Hesary acknowledges the financial support of the Japan Society for the Promotion of Science (JSPS) Kakenhi (2019–2020) Grant-in-Aid for Young Scientists (19K13742), and Grant-in-Aid for Excellent Young Researcher of the Ministry of Education of Japan (MEXT).

**Conflicts of Interest:** It is submitted that the manuscript mentioned above is initially written in all aspects and submitted for the possible publication in the journal *Sustainability*. This manuscript tries to fill the gap of literature for the other essential factors, mostly renewable energy, for the smooth and quick trajectory of EKC for developing economies. We declared no conflict of interest among all authors, and they unanimously agreed to possible publication in *Sustainability*.
