Since the last decade when China surpassed United States as the biggest carbon dioxide emitter in the world, the emission of China continued to surge, exceeding 9.8 billion metric tons in 2017. However, when it comes to emission per capita, countries like Qatar and United Arab Emirates ranked top on the list, at over twice or even three times of that of China. As a developing country, China had been excluded in some international binding agreements regarding reduction of carbon emission, such as the famous Kyoto protocol. But with Chinese citizens also starting to experience environmental degradation and hence a growing concern over the quality of the environment in China, the Chinese government had introduced policy instrutments to cope with the issue. For instance, in the "Made in China 2025" strategic plan, China planned to reduce the carbon emission intensity by 22 percent by 2020 and subsequently 40 percent by 2025, along with other parameters such as water usage and industrial energy intensity.
Aside from growth in carbon dioxide emission, emission of sulphur dioxide, nitrogen oxide as well as soot (dust) in China had decreased in the last few years. Sulphur dioxide emission in China peaked around 2005 to 2006 at around 25 million tons nationwide, which had been gradually decreasing until finally fall under ten million tons in 2017. Similar trends were observed for nitrogen oxide and soot emission in China.