Public anger is sparking more protests over China's deteriorating environment, warned Mr Zhou Shengxian, chief of the State Environmental Protection Administration (Sepa), in a report by Xinhua news agency.

He did not give figures or examples of the 'growing number of mass incidents' - a term officials use when referring to riots, demonstrations and protests - but said his office received 1,814 petitions from citizens 'appealing for a better environment' in the first five months of the year, an 8 per cent increase from the same period last year.

'China's environment is facing extremely difficult conditions,' he said in his address to a national environment meeting on Wednesday.

'Unlawful environmental acts are widespread and are the biggest challenge to our environmental protection work,' he added, lambasting local governments for shielding local businesses from pollution controls and checks.

Mr Zhou is the second environmental official to sound the alarm over the impact of China's dire environment - in particular the severe pollution of its water resources - on social stability this week.

On Tuesday, Sepa's vice-director Pan Yue did not mince his words when he told state media that 'traditional ways of development have caused the near-breakdown of China's resources and environment; and people's lives are in great danger'.

He said the battle against water pollution had 'become a severe test of the government's ability to rule, carry out macroeconomic-control policies and promote social harmony'.

Their willingness to touch on social unrest, considered a politically sensitive topic in China, suggests a growing awareness among officials that pollution incidents have shaken public confidence in the government's prevention and clean-up efforts.

It also hints at Sepa's own frustration at failing to get polluters to toe the line despite years of issuing warnings and strong measures aimed at reining in polluting industries and shifting local governments away from a blind pursuit of growth.

Beijing's discomfort over anything that draws attention to or could be a potential trigger for social unrest in the country was underscored by a Financial Times (FT) report earlier this week.

It said Sepa and Chinese health officials pressured the World Bank into removing information which estimated that 750,000 Chinese a year die prematurely because of air and water pollution. Chinese officials had doubts over the method of calculation and were worried about the social consequences of making the information public, said the FT report.

But a spokesman for China's Foreign Ministry yesterday denied the report, saying 'the issue that China has requested the World Bank to delete related data does not exist'.

Over the past two months, outbreaks of blue-green algae have been reported in eastern Taihu Lake, Chaohu Lake and south-western Dianchi Lake, tainting local tap water supplies.

This week, water supply to 200,000 people in Shuyang county in eastern Jiangsu province was cut for more than 40 hours after a chemical spill.

Mr Zhou vowed to make cleaning up pollution in China's main rivers and lakes a priority for the rest of the year.

Mr Pan announced that Sepa will reject new projects in 13 locations along the Yangtze, Yellow, Huai and Hai rivers, and has ordered 32 heavily polluting factories and six wastewater plants to clean up in three months in order for local development to resume.

He said companies that violate environmental rules will be barred from getting bank loans.

A Cabinet meeting led by Premier Wen Jiabao on Wednesday also approved a draft amendment to the water pollution law, calling for more testing, licensing and stiffer penalties.

Still, Mr Pan cautioned that local corruption and protectionism could thwart efforts to turn things around.

Given that past Sepa orders have been widely ignored, Mr Pan told the China Daily: 'To be frank, I am not optimistic.'

tracyq@sph.com.sg