The mainland's top environmental agency has announced an investigation into the state of the nation's rivers and waterways - the biggest water-pollution survey in years. The Ministry of Environmental Protection's project comes after a string of massive pollution incidents and a grim warning by Greenpeace last week that the Yangtze River was turning cancerous. Zhang Lijun , vice-minister for environmental protection, announced the survey - which is to focus on petrochemical plants and oil depots - at an internal meeting on Friday, but it was reported by mainland media only yesterday. 'The current environmental-safety situation is still extremely severe,' Zhang told the meeting, adding that the 119 environmental incidents the agency had handled in the year so far represented a 35 per cent jump over the same period last year. Some 70 per cent of those incidents involved chemical products. Zhang pointed out that in just the past two months there had been a big explosion and oil spill at a PetroChina pipeline in Dalian, Liaoning , a huge explosion caused by a ruptured gas main in Nanjing, Jiangsu, and the massive leak of toxic chemicals into the Songhua River in Jilin province . 'Speaking from the fundamentals, there are still some areas which are overlooking environmental safety during this rapid economic development, resulting in long-term cumulative problems,' Zhang said. The survey would begin on September 17, with various industries responsible for self-inspection during the first month, followed by an inspection by local environmental authorities from 'mid-October to mid-November'. Reports would be due by the end of November. Zou Shoumin, head of the ministry's investigation department, told the 21st Century Business Herald that the survey would look into more than 400,000 businesses. 'The size of the task is massive, and over just two months, the time scale is also very tight,' Zou said. Ma Jun, director of the non-governmental Institute of Public and Environmental Research, poured cold water on the initiative, saying it was unlikely to have any impact on big sources of pollution. 'The Ministry of Environmental Protection has done many similar studies in the past, but they do not release the results,' Ma said. 'As there is no complete transparency in the reporting of the ministry's findings, the public cannot have any confidence in them. It is good that the ministry is surveying the situation, but simply having that information will not do anything to control the pollution.' He reiterated the long-standing and widely held criticism of the ministry as a toothless agency. 'The ministry's powers are very limited,' Ma said. 'We will never see any real improvement until there is proper enforcement of the regulations.' Greenpeace said in its report last week that the mainland was failing to meet its international commitments to clean up the river, which remained awash with toxic chemicals that posed health risks for tens of millions of people. It said hazardous chemicals - including heavy metals and carcinogens - were regularly found in fish caught in four cities along the river: Chongqing; Nanjing; Wuhan, Hubei province ; and Maanshan, Anhui . Pressure has also been mounting for the ministry to step up protective measures in the wake of a series of high-profile spillages and other accidents in July. About 1,500 tonnes of crude oil leaked into the sea, polluting a 430 sq km area, in the Dalian spill. A massive gas explosion tore through a residential district in Nanjing, destroying homes and damaging buildings within a one-kilometre radius and killing 13 people. And in Jilin, as many as 7,000 barrels containing toxic chemicals were swept into the Songhua, threatening to contaminate the water supply for millions of residents.