Ecological problems of modern central Kazakhstan: challenges and possible solutions Тurgai Alimbaev, Zhanna Mazhitova, Bibizhamal Omarova, Bekzhan Kamzayev and Kuralai Atanakova E3S Web Conf., 157 (2020) 03018 Published online: 20 March 2020 DOI: 10.1051/e3sconf/202015703018