China's air pollution increased this year for the first time since 2005, the environmental protection ministry has said, due to sandstorms, a rise in construction and industrial projects, and more cars.

The ministry found that the number of "good air quality days" in 113 major cities across the nation had dropped 0.3 percentage points in the first six months of the year compared with the same time last year.

These cities had not recorded a fall in the number of good air quality days since 2005, Tao Detian, spokesman for the ministry, said in a statement on its website dated Monday.

The level of inhalable particles, a major air pollution index, was also up during that time in those cities for the first time since 2005, Tao said, blaming the deterioration in air quality on severe spring sandstorms.

"More construction and industrial projects that started this year due to economic recovery and the rapid increase in automobiles should also be blamed," Chai Fahe, vice head of the Chinese Research Academy of Environmental Sciences, told the China Daily newspaper.

The ministry also found that more than a quarter of surface water in China was contaminated, and fit only for industrial or agricultural use.

Acid rain was also a problem in the first half of the year -- out of 443 cities the ministry monitored, 189 suffered from the harmful precipitation.

And in eight cities, including a district of Shanghai, the rain that fell for the first six months was constantly acid, the statement said.

Tao said that despite some improvements, China still faced a "grim" situation in fighting pollution.

China has some of the world's worst water and air pollution after rapid industrialisation over the last 30 years triggered widespread environmental damage.

A report published in March by the London-based medical journal The Lancet said air pollution in the Asian nation was widely to blame for 1.3 million premature deaths a year from respiratory disease.