Income inequality in China has been increasing as the country's economy grows, leading to worse environmental quality. By studying data from different provinces, researchers found that as the income gap widens, carbon emissions per person also increase. They used a method called Generalized Method of Moments to analyze this relationship. Additionally, they discovered that as per capita income rises, carbon emissions initially decrease before increasing again. Furthermore, increasing the value-added share of secondary industry in the GDP leads to higher carbon emissions per person.