Coastal villages have become the victims of booming development across the border as thousands of tonnes of industrial, livestock, and human waste are dumped into the rivers of Shenzhen. The lack of treatment plants and loose controls on the Shenzhen side have also undermined Hong Kong's work to clean up water. Fishermen have complained about dirty and smelly water in Deep Bay, despite it being declared a water control zone. The bay, also known as Shenzhen Bay, is fed by the polluted Shenzhen River. The 20-kilometre Shenzhen River drains a catchment area of 300 square kilometres, including Mai Po marsh - one of the largest remaining stands of mangroves on the South China coast. Shenzhen officials have admitted the city's growth has overloaded waste disposal facilities, planned for a population of up to one million. Latest census figures show Shenzhen has three million people. Shenzhen's Futian Environmental Protection Department director Liu Manheng said: 'Water quality of the rivers in Shenzhen has worsened quickly. Rubbish and animal carcasses can be seen floating on many of the rivers. 'What has caused concern is that the rivers flow into Shenzhen Bay,' said Mr Liu. Futian is a satellite town of Shenzhen situated on the northern coast of Deep Bay. Shenzhen Environmental Protection Bureau said about 46 million tonnes of waste water was discharged by households and industries last year. That was 10 per cent more than the 1994 figure. With two treatment plants, only 10 per cent of the household waste water could be treated, while 97 per cent of industrial waste water was treated. Laws require factories to instal treatment facilities. A bureau spokesman said it was aware of the problem and had planned to build two more water treatment plants in Lowu and Nanshan districts. In Hong Kong, Ping Shan rural committee vice-chairman Wong Hing-lung said: 'Borders restrict people; but dirty water does not respect boundaries. It is no use for Hong Kong to clean up its water when the Shenzhen side is dumping waste into it.' Mr Wong said many oyster farmers had been driven out of the trade because of Deep Bay's dirty water. Green Power vice-chairman Dr Ho Kin-chung said: 'Part of the problem in Shenzhen is that there are many small farming households discharging untreated waste into rivers.' Acting principal environmental protection officer Dr Yeung Hung-yiu admitted that the water quality in Deep Bay remained unsatisfactory. He said a consultancy study was under way and it was hoped to come up with new measures by the end of next year. He said both Shenzhen and Hong Kong had been aware of the pollution problem in Deep Bay and it was a priority of the Hong Kong Guangdong Environmental Protection Liaison Group.