BEIJING - The air quality in Beijing-Tianjin-Hebei and neighboring areas became worse in the period from October 2018 to January 2019 compared with a year earlier, official data showed Wednesday.

During the four months, the average density of fine particulate matter PM2.5 in 28 cities in the region rose 6.7 percent to 80 micrograms per cubic meter, the Ministry of Ecology and Environment said in a statement.

Three cities - two in Hebei province and one in Shandong - saw the average PM2.5 density drop year on year, three saw no changes and the remainder experienced rises in average density, the data showed.

In February and March, Beijing, Tianjin, Hebei and neighboring areas had unfavorable meteorological conditions for pollutants to disperse, including higher temperatures than normal, less rain and weaker cold fronts, the statement said.

According to a plan for fighting air pollution during this winter and spring, the target is that the average density should drop by about 3 percent in the four-month period.

The data also showed the air quality in the Yangtze River Delta region improved, with the average PM2.5 density down by 12.9 percent from a year earlier.