BEIJING - China is aiming to effectively curb emissions of major pollutants and ensure greater environmental quality, as pointed out in a strategic report released on Thursday by the country's leading environmental experts.

The study, jointly published by the Chinese Academy of Engineering (CAE) and the Ministry of Environmental Protection (MEP), says the government's intensified and persistent efforts to control pollution have paid off by cutting emissions of major pollutants.

"China now faces more pressure on pollution control than any other country in the world. Challenges facing the environment and natural resources are among the harshest," said Zhou Shengxian, environmental protection minister, at the study's launch ceremony on Thursday.

"As a result, the task of solving these problems is also the toughest."

It may still take China two decades to fully rein in rampant pollution, rapid ecological degradation and the loss of valuable species, according to the roadmap laid out by the study.

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"The target is to effectively curb emissions of major pollutants and ensure environmental safety by 2020," it said, adding that industrial pollution in urban areas should be brought under control and the safety of drinking water guaranteed.

By 2030, the country will see a comprehensive improvement in its environmental quality, in both urban and rural areas, with pollutants being well managed.

"That is to say, toxic pollution caused by heavy metals and persistent organic pollutants, which are quite difficult to tackle at the moment, will be fully controlled by 2030," Xia Guang, head of the policy research center for the environment and economy under the MEP, told China Daily.

Emissions of some conventional pollutants, such as sulfur dioxide from coal combustion, have already peaked in China, thanks to stringent environmental policies adopted over the past five years, said Xia.

Other pollutants, such as nitrogen oxide and ammonia nitrogen, are likely to peak in the near future, he said.

But at the current stage, overall pollution has been expanding despite the drop in emissions of major water and air pollutants, it said.

For instance, the study said, 320 million rural people still do not have access to safe drinking water in China and, of these, 190 million use drinking water that contains excessive levels of hazardous substances.

When the study was conducted, in 2007, about 30 percent of cities failed to reach national standards for air quality. Over half suffered from acid rain, with an increased acidity, compared to previous years, a result of greater fossil fuel consumption.

Reasons for the current gloomy environmental situation are because of China's inability to break out from an outdated growth mode characterized by high energy and resource consumption and high levels of polluting emissions, according to the seven-volume, six-million-word study, China's Macro Strategies for Environmental Protection.

"The significance of environmental protection and sustainable development is still poorly acknowledged at local level," said Shen Guofang, a member of the CAE, who was also one of the chief editors of the study.

"Some local governments are still blindly seeking a growth path that is heavily priced with resource depletion and environmental deterioration."

Meanwhile, a total of 10 million hectares of agricultural land has been polluted.

For the first time the study links health problems - such as increased cancer rates - with the worsening environment.

"In rural areas, the continuous increase in prevalence and the death rate from malignant tumors in the digestive system, such as liver and stomach cancer, is closely linked with environmental pollution," the study said, citing drinking water contamination and soil pollution as possible causes for the emergence of several cancer villages.

City residents are not spared, with 185 million urban dwellers perennially exposed to substandard air quality and over 30 percent of respiratory diseases attributed to atmospheric pollution, according to the study.

Pollution also contributed to rising birth defects, with a sharp increase from 8.87 per thousand in 1996 to 14.79 per thousand in 2007, it said.