This was reflected by the increase in the amount of drinkable water in seven major rivers, including the Yangtze and the Yellow River, by seven percentage points year on year to 50 per cent last year, he said.

Acknowledging the difficulty of achieving the reduction target, he called for the establishment of a high-level co-ordination mechanism to tackle the problem of upstream and downstream water quality.

While sewage treatment plants should be further developed, authorities at all levels should also increase investment in anti-pollution projects as well as develop new technology to reduce pollution, he said.

He also stressed the need to educate the public on the need to improve water quality, while calling for the strengthening of the management of water-resources protection zones.

Other measures included a regular assessment of the sources of drinking water as well as the establishment of an alert system.

Despite the authorities' pledges, Ma Jun , director of the Beijing-based Institute of Public and Environmental Affairs, said lax enforcement remained a serious problem because of local protectionism.

'Many enterprises still do not comply with the [pollution emission] standard set out by the authorities,' said Mr Ma, pointing out that many local authorities were still more concerned about their GDP growth rates at the expense of the environment.

While sewage treatment plants certainly were one key to reducing pollution, they ended up becoming polluters themselves because of their substandard structure, he said.

The environmental watchdog had long been criticised as a 'paper tiger' when it was called the State Environmental Protection Administration.

But although it has been elevated to ministry status this year, Mr Ma said it had changed in name only. 'All of its structure and power remain the same as before,' he said.

'It is still under huge pressure from local authorities when pushing forward various initiatives.'

Huo Daishan, an environmental activist monitoring the pollution of the Huai River, said the most urgent task for the authorities was to enhance co-operation among authorities both upstream and downstream.

'Each authority looks after only one section of the river, which is simply unrealistic as any pollution spreads over the whole stream,' Mr Huo said.

He also called for more public participation in monitoring the pollution system and for a fully-fledged alert system to be established.

Authorities are aiming for a 10 per cent cut in emissions of sulfur dioxide and chemical oxygen demand in their 11th five-year plan, from 2006 to 2010. But so far they have only achieved an overall reduction of 3 per cent.

Cleaning up

Overall emissions of sulfur dioxide - an industrial pollutant that induces acid rain - dropped by this much in the first half of the year from the same period last year: 3.96%