Ningbo's air quality met national standards on 91.5 percent of days from January to July, the highest rate in the past three years, according to official data from the Ningbo municipal bureau of ecology and environment. 

The figure represented an uptick of 6.6 percent over the same period in 2017. 

In the first seven months, the average PM2.5 level was 23 micrograms per cubic meter, 14 micrograms less than than the same period in 2017. 

This is largely due to efforts made by local authorities to reduce pollution.

For the first time, Ningbo ranked among the top 20 in terms of air quality among 168 major cities across the country in the first quarter. 

In the past three years, Ningbo has shut down or rectified 2,000 polluting enterprises and upgraded 49 small and micro-sized industrial parks.

In addition, the transformation of the coal yard of Datang Wushashan Power Plant, which cost more than 200 million yuan ($28.98 million), is completed. 

Furthermore, the city has invested 1.7 billion yuan into the treatment of pollution caused by industrial volatile organic chemicals, which has led to a reduction of 18,000 metric tons in emitted VOCs over the past three years.

Meanwhile, a remote monitoring system has been put in place in Ningbo to manage diesel vehicles. A total of 517,000 vehicles have been examined via remote sensing technologies this year to date, among which 193 were penalized for excessive discharge. 

This year, the city plans to set up a PM2.5 monitoring system covering 155 towns and sub-districts across the city.