As we become richer and richer, we are producing more and more rubbish. The Asian Development Bank(ADB) says that our largest cities produce 760 000 tons of solid waste every day. It predicts  that there will be an increase--to 1.8 million tons--by 2025. It seems too much to deal with. "The growing waste is simply trying to cover our cities," says Michael Lindfield, a specialist of ADB in Manila.  _ The World Bank says some governments are spending as much as half of their budgets  dealing with rubbish. And even so, it is common that half of all the waste goes uncollected. Much of the added difficulty is packaging from consumer products and the products themselves--all of which need years, even centuries to decompose . Lindfield believes that four of every five products we buy are thrown away after a single use. It all makes the work to deal with solid waste much more expensive. The rubbish is more than just an environmental problem--it also influences national economies  by disturbing the world market, discouraging tourism and slowing down industrial development. Lots of rubbish also influences the look of our cities. As he walks to work from his home in Bangkok every day, Chatchat Mutita, a 36-year-old advertising specialist, must pass a lot of ugly, smelly rubbish that isn't collected until late at night. He says things get worse when it rains because some yellow water will stream from the rubbish to the sidewalk. Modern technology can make the problems of open dumps less serious. But Chettiyappan Visvanathan, a professor at the Asian Institute of Technology in Pathumthal, Thailand, believes that there are no engineered facilities  in nine of every ten dumps all over the country. Some countries depend on most solid waste to produce energy, but there's a growing problem of air pollution. Burning is far more dangerous than open dumps. The ADB says the growing rubbish must be dealt with by the "3Rs" --reducing the waste, reusing things that are being thrown away and recycling materials. Which of the the following can be the most serious problem rubbish brings to us?
It causes a lot of difficulty cleaning up our cities. It stops our nation economies from developing. It makes our environment uglier and dirtier. It brings air pollution, water pollution and diseases.