North China's Hebei Province, which neighbors Beijing and is known for its steel industry and severe smog, saw its average PM2.5 density drop 5.8 percent in 2019.
Xu Qin, governor of the province, made the announcement Tuesday when delivering a government work report at the opening of the local legislative session.
PM2.5 is a measure of the density of hazardous particulates in the air. Xu said Hebei enjoyed the best air quality in six years.
In 2019, the province established a database to monitor and record the emissions of 55,600 enterprises, replaced coal-fired heaters with clean energy facilities and cut coal and steel capacities.
Xu said the province would continue to combat smog and vowed to lower the average density of PM2.5 by around 3 percent in 2020.