Heavy smog is forecast to remain at severe pollution levels across northern China, including Beijing, Tianjin and Hebei province, for another two days, the Ministry of Environmental Protection said on Sunday.

The capital issued its first orange alert of 2015 on Sunday, the second-highest response to smog, to restrict pollutant emissions. Hebei province also announced an orange alert.

Beijing exposed on Sunday afternoon six companies and construction sites which failed to suspend their production as required.