The green belt on New Delhi's outskirts will get gobbled up as the city follows on the path of major cities such as Beijing and turns into a concrete jungle, states a new UN report.

"One Planet Many People: Atlas of Our Changing Environment" says by 2010, Delhi will be home to 21 million people.

Produced by the UN Environment Programme (UNEP), the report compares and contrasts spectacular satellite images of the past few decades with contemporary ones, some of which have never been seen before.

The atlas, produced in collaboration with organisations like the US Geological Survey and space agency NASA, highlights the threat to environment from growth and changes around some major cities such as Beijing New Delhi and Santiago.

"The dramatic and, in some cases, damaging environmental changes sweeping planet earth are brought into sharp focus in the new atlas," UNEP said in a statement.

Among Asian countries, Beijing has undergone tremendous growth since the start of economic reforms in 1979.

The satellite images underline just how tremendous this has been, with Beijing mushrooming from a small central area to one that has turned towns some distance away, such as Ginghe and Fengtai, into suburbs.

The expansion is seen to have also gobbled up the deciduous forests to the west and the rice, winter wheat and vegetable plots that once surrounded the city.

"A similar, huge expansion is seen for Delhi," said UNEP.

In 1975, New Delhi's population was swelling. "By 2000 the city had well over 12 million inhabitants. By 2010 it is set to rise to nearly 21 million," UNEP said.

The latest satellite images show Delhi's growth concentrated in the suburbs of Faridabad, Ghaziabad and Gurgaon.

Researchers hope that the "One Planet Many People" atlas will awaken governments, private business, NGOs and private individuals by highlighting how globalisation is driving local and regional change.

"Cities pull in huge amounts of resources, including water, food, timber, metals and people. They export large amounts of wastes, including household and industrial wastes, wastewater and the gases linked with global warming. Thus their impacts stretch beyond their physical borders affecting countries, regions and the planet as a whole," said Klaus Toepfer, UNEP's executive director.

"The battle for sustainable development, for delivering a more environmentally stable, just and healthier world, is going to be largely won and lost in our cities," warned Toepfer.

The huge growth of greenhouses in southern Spain, the rapid rise of shrimp farming in Asia and South America and the emergence of a giant, shadow puppet-shaped peninsula at the mouth of China's Yellow River are among a string of curious and surprising changes seen from space.
 
They sit beside the more conventional but no less dramatic, images of rain forest deforestation in Paraguay and Brazil, rapid oil and gas development in Wyoming in the US, forest fires across sub-Saharan Africa and the retreat of glaciers and ice in polar and mountain areas.