The U.N. children’s agency is warning that the health of 11 million children in Pakistan’s eastern Punjab province is in danger because of air pollution that experts say has become a fifth season in r

The United Nations has called for immediate and greater efforts to reduce air pollution in Pakistan, highlighting the alarming impact on children’s health. More than 11 million children under five years of age in Punjab province are exposed to toxic smog, the UN warned on Monday.

Punjab authorities have banned most outdoor activities and told some shops to shut early as smog-induced illnesses soar. Schools have also been closed to protect children, who are at high risk from the pollution.