The sandstorms turned skies in East Asia orange and pushed pollution indices in many Asian cities to new highs.

Media in Japan and Korea blamed the sandstorms on 'rapid deforestation' in China and said Beijing's reckless pursuit of economic development had brought environmental woes to its neighbours.

Experts from China's national meteorological administration yesterday denied the accusation, saying that the storms of sand and dust were caused by global climate change. They said there was no evidence showing there was deforestation in northern China.

'According to data and images collected from our monitoring satellites, the forest coverage in February this year is the same as the same period in 2009,' an unnamed expert from the administration told Xinhua.

He said a study showed that 40 per cent of the sand and dust that formed the recent giant sandstorm had come from 'outside China'. The expert said that apart from the Gobi, deserts in Mongolia and Central Asia were also key sources of sandstorms.

The expert admitted that human activities, such as rapid industrialisation, did make the situation worse. But he said only 6 per cent of the desert land in China was caused by human activity and its size was decreasing every year.

Citing the fourth assessment report of the Intergovernmental Panel on Climate Change released in 2007, the expert said the chief cause of sandstorms in Asia was extreme meteorological events, not deforestation.

Sandstorms from the mainland have become an annual phenomenon over the past decade. Each year harmful 'yellow dust' hits Japan and Korea, forcing school closures and causing tension between neighbouring nations.

Japan and Korea have repeatedly called for Beijing to share information and boost transparency to help them prepare.

Troubled skies

China denies that deforestation is to blame for dust clouds

Number of mainland provinces and municipalities covered by sandstorms since Friday: 21