BEIJING -- This capital city of more than 11 million inhabitants is running short of water. It releases most of its household and industrial wastewater untreated. In the winter, concentrations of hazardous chemicals and particles in its air are at times among the highest in the world.
Then, in the spring, comes the yellow dragon -- suffocating, wind-borne clouds of fine yellow dust from the Gobi desert more than 200 miles away.
Because of a decade-long campaign to plant trees in Beijing -- part of a massive effort to build a 4,000-mile-long "green great wall" of trees across all North China -- the number of days that the capital is positively choked by dust has been fewer in recent years, down from about 30 such days annually in the 1970s to only about 12 a year now.
But each spring, when northwest winds take aloft the newly thawed topsoil of the Mongolian plateau, the resultant clouds of sand can still enshroud the city completely.
Last April, Beijing's worst dust storm in 70 years rolled in on gale-force winds -- turning the city's sky a sick yellow-orange, dropping visibility on its vast avenues to 40 yards, closing its airport and forcing those who had to venture outside to lean into the gritty force with their heads encased in scarves.
Nothing, not even windows taped shut, could keep the dust out of Beijing's dwellings.
"I thought it was the end of the world," recalled one of the city's 5,000 street sweepers, who from April to October toil daily in a never-ending battle against the encroaching desert.
For all its dust -- and all its air and water pollution -- Beijing offers far from the worst living environment in China, a giant of a country with giant-sized pollution problems.
The air pollution in Shenyang, a heavily industrial city of almost 3 million residents in Liaoning province to the northeast, is considered the second worst in the world, behind Mexico City's. In 1988, the smog got so bad in Benxi, a smaller iron-and-steel city in the same province, that it disappeared from view on satellite photos.
All across China, there is mounting evidence that 40 years of rapid and at times misguided industrialization has far outstripped only recently launched environmental protection efforts -- so much so that some Western experts fear that parts of China may be environmentally exhausted before the country ever fully industrializes.
Eighty percent of China's rivers are polluted. Sixty-five percent of its people drink non-potable water. Ninety percent of its cities have no wastewater treatment. Two-thirds of its larger cities face water shortages. The air quality in almost all its major cities cannot meet international health standards.
Beijing's own environmental problems stem in part from its ill-chosen site, backed up against a half-ring of mountains on the northern edge of the semiarid North China plain.
What looked like a good place for a capital to the Mongol conqueror Genghis Khan 700 years ago turned out not to be such a favorable locale for a densely populated metropolis, where chemical plants and other heavy industries were concentrated in the 1950s, where crops are sown in suburban areas and where residents still mainly rely on low-grade coal for power and heating.
Nor was it a good spot to have launched a disastrous, Maoist-style mass campaign for a while more than 30 years ago to get rid of the city's grain-eating birds and insects by cutting down most of its trees and pulling up much of its ground cover.
An impressive tree-planting campaign in Beijing, under way for a decade and reaching a high pitch this year before September's Asian Games, now has reversed a good deal of the environmental damage that was done in the 1950s.
Last year alone, more than 15 million trees were planted in Beijing and its suburbs, officials claim, along with 1 million square meters of new grass. The city's per capita amount of green space has risen about 20 percent in the past 10 years, even as its population has continued to balloon.
The capital's afforestation efforts are just a small part of the ambitious but troubled "green great wall" project. The largest environmental endeavor in the world, its aim is to curb the rapid southeastward drift of the sprawling deserts to the north and west of the capital by creating a more than 250-mile-wide belt of trees stretching across 13 North China provinces and regions.
Although this project has given China the claim of the world's greatest tree planter -- 1.7 billion trees were supposedly planted last year -- even the Chinese press has reported that half the official total of newly planted saplings is false and that only about 60 percent of the other half has survived pests and drought.
Nevertheless, Beijing's increased forest cover -- along with efforts to relocate heavy industry out of the city's center and to shift to low-sulfur coal briquettes for home heating and to gas for cooking -- has improved the capital's air quality.