Air quality has improved across China in the first six months of this year, despite growing concentrations of ground-level ozone, according to a new report.

The Ministry of Environmental Protection released its report on air and water quality for the first half of the year on Sunday, with six cities in Hebei province listed among the top 10 most polluted, with Baoding the worst.

Haikou in Hainan province had the best air quality in the first six months, the ministry said.

Luo Yi, head of the ministry's environmental monitoring department, said improvements had been noted in all 338 cities that are monitored nationwide, with the average air quality in 78 cities now meeting national standards, a year-on-year increase of 6.5 percent.

Large reductions in major airborne pollutants have also been recorded, the ministry said.

For example, in the Beijing-Tianjin-Hebei cluster, concentrations of PM2.5 - fine particulate matter with a diameter less than 2.5 microns that is hazardous to human health - have been reduced by 45.2 percent compared with the first six months of 2013.

PM10 concentrations in the region were also 40.9 percent lower than in 2013, the report said.

Elsewhere, cities in the Yangtze River Delta have witnessed PM2.5 and PM10 reductions of at least 15 percent compared with the same period in 2013, while cities in the Pearl River Delta also saw reductions of at least 13 percent.

However, ground-level ozone concentrations in the Beijing-Tianjin-Hebei cluster increased by 16.4 percent in the first six months of the year, compared with the same period in 2013, while the Yangtze River Delta also saw an increase of 9.9 percent.

Improvements have been noted in surface water quality, the ministry's Luo said.

Of the 1,940 testing stations nationwide, 68.8 percent reported water quality that was ranked in the top three tiers of the national six-tier system.

This was a year-on-year increase of 2.8 percent, according to the report.