So Paulo, Brazil – imagine a modern metropolis with no outdoor advertising: no electronic panels with messages crawling along the bottom. Come the New Year, this city of 11 million, overwhelmed by authorities call 「visual pollution,」 plans to press the 「delete all」 button and offer its residents an unimpeded view of their surroundings.

But in proposing to transform the landscape here, officials have unleashed debate and brought into conflict sharply differing conceptions of what this city, south America's largest and most prosperous, should be. City planners, architects and environmental advocates, for instance, have argued enthusiastically that the prohibition, through a new 「clean city」 law, brings So Paulo a welcomes step closer to an imagined urban ideal.

The law is 「a rare victory of the public interest over private, of order over disorder, esthetics over ugliness, of cleanliness over the trash,」 Roberto Pompeu de Toledo, a columnist and author of a history of So Paulo, wrote recently in the weekly newsmagazine Veja. 「For once in life, all that is accustomed to coming out on top in Brazil has lost.」

Advertising and business groups, though, regard the legislation as injurious to society and an affront to their professions. They say that free expression will be inhibited, jobs will be lost, consumers will have less information on which to base purchasing decisions and even that streets will be less safe at night with the loss of illumination from outdoor advertising.

「This is a radical law that damages the rules of a market economy and respect for the rule of law,」 said Marcel Solimeo, chief economists of the commercial association of So Paulo, which has 32,000 members. 「We live in a consumer society, and the essence of capitalism is the availability of information about products.」

The statute says that outsized billboards and screens that dominate the skyline here will have to come down, as well all other forms of publicity in public space, such as disturbing fliers.

But the law also regulates the dimensions of store signs and will force many well-known companies to reduce them substantially by a formula based on the size of their facades. Another provision outlaws advertising of any kind on the sides of the city thousands of buses taxis.

「What we are aiming for is a complete change of culture,」 said Roberto Tripoli, president of the city council and one of the main sponsors of the legislation. 「Yes, some people are going to have to pay a price. But things were out of hand, and the population has made it clear it wants this.」

This law, approved by a vote of 45 to 1 in September, goes into effect on January 1. Opponents complain that does not allow enough time for merchants to comply, that fines of up to $4500 for violations are extreme and that the result will inevitably be a diminishing of urban life – 「like New York without Times Square or Tokyo without Ginza,」 Mr. Solimeo said.

But popular reaction has largely been supportive. 「I'm in favor of anything that improves the way this city looks, and this law definitely makes thing better,」 said Fernando Gil, a 25- year-old student interviewed on Avenida Paulista, the main street in the heart of the financial district. 「All that neon and bright lights, it is just doesn't fit here.」