BEIJING -- Beijing Municipality filed 13,127 environmental protection violation cases in 2016, with fines worth a total of 150 million yuan ($21.8 million), local environmental authorities said Wednesday.

A total of 10,184 cases, receiving fines totalling 8.7 million yuan, were due to pollution from mobile emission sources. Among these, more than 10,000 vehicles were punished for excessive exhaust emissions.

Fines totaling 142 million yuan, involving 2,943 cases, were issued for fixed pollution emission sources. Nearly half of these violations were reported for air pollution.

Beijing authorities carried out a series of measures to tackle air pollution in 2016, such as cutting coal consumption, ordering construction sites to reduce dust, and removing high-polluting vehicles from roads.

In Beijing, air pollution indicators have registered steady annual declines. In 2016 PM2.5 levels fell 9.9 percent from the previous year.