“…Few researches emphasize on the income inequality variable and empirically examine the effect of income inequality on environmental quality (Torras & Boyce, 1998;Scruggs, 1998;Magnani, 2000;Marsiliani & Renstorm, 2000;Ravallian et al, 2000). However, this issue has been considered a bit more recently, and it is believed that to avoid the miss specification, a criteria of income inequality should be considered in the EKC investigation (Jorgenson et al, 2017;Grunewald et al, 2017;Bae, 2017;Liu et al, 2018;Masud et al, 2018;Liu et al, 2019;Uzar & Eyuboglu, 2019;Ridzuan, 2019;Uddin et al, 2020;Chen et al, 2020;Huang & Duan, 2020).…”