Hundreds of cities across China enjoyed around 130 days without serious air pollution in the first half of 2015, the Ministry of Environmental Protection (MEP) said on Monday.
Only around 28 percent of days in the 338 cities failed to meet the government's air quality standards, according to a MEP report on China's overall environmental condition, an improvement on the same period last year.
In 2014, the 161 cities monitored that year saw around 110 days without serious air pollution in the first six months of the year.
The government's pollution standards state that each day should have an average air quality of less than 75 micrograms of particulate matter - tiny particles that can cause long-term health problems - smaller than 2.5 micrometers in diameter per cubic meter of air.
The report added that of the 898 drinking water sources monitored in China, 95 percent of surface water sources and 87 percent of groundwater sources met safety standards.
However, there has only been a marginal improvement in the number of cities suffering from acid rain, with 164 out of the 470 cities that monitor the phenomenon reporting incidents of acid rain between January and the end of June, only two less than in the same period last year.
Most cities that measure their level of air pollution have seen noise levels dropping, the report said, adding that the situation in provincial capitals remains below average.
The report found out that six of the 10 cities with the worst air quality were in Hebei Province.
