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.