THE clean-up of China will cost US$200 billion, most of which must come from overseas investment, according to Yu Yuefeng, vice-president of the China Association of Environmental Protection Industry. Mr Yu said it would cost $15 million to clean the city of Guangzhou alone. Pollution control was beyond China's means, but investing in the mainland's environmental protection meant having a stake in the market for green technology to emerge in the next two to five years, he said. The Private Sector Committee Environment Centre estimated the global market for environmental technologies to reach $600 billion by the turn of the century. ''We will need investments internationally and locally. Environmental degradation is an obstacle in the market which cannot be solved by China alone,'' Mr Yu said. He called on foreign companies to help China develop its own technology to stop environmental degradation resulting from massive industrial development. ''Chinese technology is cheap and practical, but only for other Asian centres. We will follow a basic strategy to use foreign investment in order to exploit the market and export overseas,'' he said. Mr Yu predicted a huge market for environmental technology, but said China's preparations depended on costly American technology. The most pressing concern was treatment of water and solid waste, which would account for 70 per cent of the $200 billion. Air pollution, for the promotion health and machine maintenance, was also a concern. China was in desperate need of dust-removal technology for both general and industrial use, Mr Yu said. Machines to extract dust and sulphur were especially needed in the southern region where manufacturing was concentrated. China was looking to foreign companies to develop better ways of treating water from wood and pulp plants, highly concentrated waste water and toxic waste. ''We have over 30,000 small pulp plants. Pollution is a concern, but closing them would cause a shortage of paper products,'' Mr Yu said. Ordinary mainlanders felt a strong need for environmental protection because of worsening pollution, but a country with per capita income below $1,000 could do little, he said. ''Now that people have bread and butter, they can worry about the environment. There is a growing awareness and concern,'' he said. Mr Yu said those countries with a per capita income of more than $3,000 must initiate the process, and countries such as Japan could be doing more to help.