Dongguan Mayor Li Yuquan told polluting Hong Kong factories yesterday they would be given up to a year to clean up their act so they could continue operating in the city. Mr Li said that instead of losing their operating licences immediately, polluting factories operating in fields such as electroplating, dyeing and printing would not be allowed to renew their licences. The factories could move into nine business parks, where waste water will be treated collectively. The move to upgrade the economy was not an excuse to drive away all polluting factories, said Mr Li. 'And we did set a cushion period for them, which was from several months to a year.' The city drew up a plan to close down, relocate and inspect 1,252 seriously polluting factories at the end of 2005. Some Hong Kong businessmen complained last year they had had no time to find new locations after the government refused to renew their licences. Of Dongguan's 15,000 foreign-invested enterprises, 58 per cent, or about 8,800, are from Hong Kong. Mr Li acknowledged that water pollution was the most serious environmental problem in Dongguan and that all rivers were black. He said 36 sewage works and 200km to 400km of main sewage treatment pipes were under construction. He said they would be done this year. Senior Guangdong officials said this week all polluting factories would be closed and could not relocate within the province. Li Qing, director of the Guangdong Environmental Protection Bureau, said the government inspected 150,000 polluting factories last year and 2,100 were closed and two people jailed.