Beijing has had better air quality for the past two weeks despite the setting off of fireworks, the best level for the same holiday period since 2013, the municipal environmental authority said.

It’s a ritual for Chinese to set off firecrackers to celebrate holidays, especially for Spring Festival, but it causes air pollution and drives the readings of airborne pollutants to hazardous levels.

But from Spring Festival eve on Feb 7 until the Lantern Festival on Feb 22, Beijing has seen 11 days with good air quality, two more than the same period last year, the Beijing Municipal Environmental Protection Bureau said.

Polluted days were reduced to three from seven in 2015, a great reduction, the bureau said.

The average reading of PM2.5 – particulate matter with a diameter of less than 2.5 microns that poses health risks – during the Lantern Festival, the last day on which residents are allowed to set off firecrackers, has been reduced by 90 percent year-on-year.

The PM2.5 reading during the Lantern Festival climbed quickly from 9 micrograms per cubic meter at 5 pm to 31 at 9 pm, meaning air quality remained at a good level. However, the setting off of fireworks and windless weather worsened air quality quickly, driving it to hazardous levels and lingering for one more day in 2015.

In addition, during the 16-day holiday period, the average PM2.5 reading was 59 micrograms per cubic meter, a reduction of 27 percent on the same period last year, the bureau said.

The bureau said the improvement in air quality was achieved because of more windy days which aided the dispersal of pollutants.