Beijing-Tianjin-Hebei region's problem is shared by many developed countries

The smog-filled Beijing-Tianjin-Hebei region has seen improvement in combating particulate pollution, such as PM2.5, since 2013, but faces worsening ground-level ozone pollution during the summers, a challenge many developed countries share, a new report from Peking University said.

The 13 cities in the Beijing-Tianjin-Hebei region last year saw the annual average concentration of ground-level ozone increase by 13.1 percent, compared with the level in 2013, the report said.