In his annual work report delivered at the congress' opening session last Thursday, re-elected governor Huang Huahua said 'development among different regions is unbalanced' and the province felt 'great pressure' from the need for sustainable development amid 'tight environmental constraints'.

In the past five years, Qingyuan has achieved rapid growth by attracting some 2,000 investment projects valued at 250 billion yuan. The projects are almost all manufacturing industries, most from the relatively developed Pearl River Delta.

The industrial relocation, an important part of Guangdong's economic restructuring strategy, has resulted in significant changes in Qingyuan, where the gross domestic product rose by more than 18 per cent a year between 2004 and 2006.

However, in 2004, the first year of its 'economic takeoff', the provincial environmental protection bureau criticised Qingyuan for being the only city in Guangdong that had failed to meet environmental standards.

Mr Chen knows that many experts and the general public are concerned about whether the mountainous areas are about to repeat the mistakes made by Pearl River Delta cities three decades ago, when polluters seriously damaged the environment.

He said pollution could be controlled with new technology and moving factories into well-planned industrial zones, but admitted that the city was only treating 35 per cent of its sewage, still 10 percentage points short of 2005 targets.

The least developed mountainous areas in Guangdong are usually upstream of the rivers that flow to the bigger, more developed cities. Qingyuan and Shaoguan are upstream of the Beijiang, while Heyuan is the source of the Dongjiang, which provides drinking water for Hong Kong.

Cheng Jiansan , an economist with the Guangdong Academy of Social Sciences, said the province should establish an ecological compensation mechanism to help mountainous areas build wastewater treatment plants.

Without financial support from the provincial government and the wealthier cities downstream, including Guangzhou, Dongguan and Shenzhen, Professor Cheng said poorer cities were not capable of protecting important river sources.

'The Dongjiang will be completely polluted in 10 to 20 years if we don't do anything now,' he said.

Investigating in Zhongxin township, Heyuan, last year, he found the water of the Zhongxin River, which joins the Dongjiang at the city's Xinfengjiang Reservoir, was being polluted by several factories that did not treat their wastewater.

Meanwhile, illegal mining of rare-earth elements and iron ore is also polluting other streams that flow into the Dongjiang in the Heyuan townships of Huangtian and Banjiang.

Banjiang villager Yu Chaoyuan said the stream beside his house, which joins the Dongjiang at the Xinfengjiang Reservoir, was yellow with pollution from illegal iron ore mining in the nearby mountains. Some parts of the riverbed were even coloured grey and blue by sulfur in the polluted water. 'Of course, we don't dare drink the water, and this dirty water will pollute the Dongjiang in the future,' he said.

Heyuan party boss Chen Jianhua announced early last week that construction of the Guangzhou-Heyuan Highway would start this year, and that people would be able to drive from Guangzhou to Heyuan in half an hour by 2010.

Professor Cheng warned that cutting travel times between the booming Pearl River Delta and the mountainous areas could result in more industries moving. Even worse, pollution could follow if the cities to which the industries moved failed to set up sufficient facilities to treat wastewater or emissions.

His colleague, Ding Li , said the central government had been working hard to solve environmental-protection compensation issues, and would introduce policies soon.

According to the 11th Five Year Programme, all provinces need to categorise districts for different industrial functions according to environmental impacts.

The areas most sensitive to pollution, such as Heyuan, would be asked to ban most manufacturing industries to protect water sources, with the provincial or even central government compensating them for their losses, Professor Ding said.

He said Guangdong's plans were still being drawn up.

National Development and Reform Commission deputy secretary general Yang Weimin said most land on the mainland would be set aside permanently for agricultural use and protected from development.