Pollution returns to northern China as industrial activities rise

BEIJING, March 6 (Reuters) - Thirteen northern Chinese cities surrounding the capital Beijing have issued pollution alerts over the last few days, raising concerns that an industrial recovery in the region is increasing smog levels.

All 13 cities, including Tianjin and Tangshan, China's biggest steelmaking centre, had issued "orange" heavy pollution alerts by Sunday, the second-highest alert, the National Joint Research Center for Tackling Key Problems in Air Pollution Control (NJRC) said.

Air quality in the traditionally smog-prone region of Beijing, Tianjin and Hebei has improved markedly in recent years as a result of a "war on pollution" since 2014, which involved closing and relocating industrial plants as well as raising emission standards.

NJRC said the recent spike had been driven by an increase in industrial activity, with steel and cement plants operating at higher levels, and diesel truck traffic also rising. It expected the smog to persist until March 10.