China's pollution problem has worsened this year as the demands of the surging economy continue to challenge anti-pollution efforts, state media reported Wednesday.

Figures released in a report by China's State Environment Protection Administration showed 12 billion tons of industrial waste water were discharged in the first half of this year, an increase of 2.4 percent from the same period last year, Xinhua News Agency reported.

Also in the first six months of this year, the water pollution index rose by 3.7 percent, while sulfur dioxide emissions increased by 4.2 percent, from the same period a year earlier.

The environment agency linked the increased pollution to the country's booming economy, Xinhua said. China's gross domestic product rose 10.9 percent in the first half of this year.

Despite a growing recognition of the severe environmental damage wrought by three decades of industrial development, heavy polluters continue to foul China's water and air due to poor enforcement of restrictions at the local level.

The environment agency has criticized local governments for disregarding efforts to reduce energy consumption and pollution.

State media also reported Wednesday that a 1.24-mile-long (two-kilometer) section of the Yellow River turned red for about an hour after being contaminated with waste water from a heating station in the western city of Lanzhou.