'HIS days are numbered," sniffs taxi driver Jose Serria Carrillo as he swings his green 1991 Volkswagen Beetle wide of a slower, rust-scarred yellow taxi.A new environmental law here requires all taxi cabs older than model year 1985 to be traded in for a 1991 model, which by law is fitted with a catalytic converter. The taxi drivers qualify for special loans and get a cab painted politically correct green. The green taxis are just one of a slew of new environmental programs designed to erase Mexico's reputation as one of the most polluted cities in the world. "We've got a $4.68 billion environmental program in a third-world city emerging from 10 years of its worst economic crisis. If that's not commitment to clean the environment, what is?" asks Fernando Menendez Garza, director of environmental projects for the Federal District. Taxi driver Serria Carrillo also uses the new unleaded gasoline introduced last year. The lead content of regular gas has been halved. And this month half of roughly 125,000 taxis and Volkswagen vans used for public transport join the Day Without a Car program that - in theory - idles 20 percent of all cars on the road.
Night deliveries To cut traffic and pollutants, the city three months ago instituted a plan for night deliveries of supplies and products to factories, stores, hotels, and restaurants. So far, 250 major firms and about 40,000 cargo vehicles are participating, city officials say. "It's not been easy to set up; coordinating suppliers, distributors, unions, stores, and police for security on routes," says Ernesto Cisneros, director of the program. "But with less traffic, the big distributors will be able to make more deliveries in less time - thus saving money." But a Pepsi-Cola Company logistics manager says the benefits have not appeared yet. "We've put on a whole extra shift of drivers and warehouse workers. So far this has meant a much greater cost of business for us," he says. Why such drastic measures? Vehicles and industry pump about 11,700 tons of pollutants into the air each day, according to government figures. Mexico City lies in a high valley (7,300 feet above sea level) surrounded by mountains that prevent winds from dispersing contaminants. Thermal inversions in winter trap gases in the valley. But even with these programs, new subway lines, and a program to replace all older public transport vehicles with newer engines or less polluting models by 1994, the use of the most contaminating vehicle per person - the automobile - continues to climb. To get around the Day Without a Car program, some people buy another car - a second-hand clunker - to use on their "no-car" day. Renewed economic growth after a decade of austerity has sent car sales soaring. "Los Angeles has the best gasoline and the highest emission standards," Menendez says, "but it has so many cars [three times as many as Mexico City] moving so slowly it has the worst ozone pollution levels in the US. That can't be the model for us. The only solution is public transport." To coax more upper- and middle-class Mexicans into this mode of commuting, private "luxury" buses are now being introduced. The other major environmental challenge for the city is a looming water shortage. Underground aquifers that provide 70 percent of drinking water are over-exploited. And pumping in water from outside the valley is proving increasingly expensive and politically controversial.
Saving the aquifers To keep the problem from worsening, the city has expropriated some 4,100 hectares (10,131 acres) in the last three years and plans to grab another 1,700 hectares (4,200 acres) before it becomes covered in concrete. The land is considered critical to recharging the aquifers. Water rates have also been hiked up to 400 percent in the past two years to reduce consumption. "It's not enough," says David Perez Lopez, director of the earth science school at the National Polytechnical Institute. "To stop the over-exploitation of aquifers and have enough water for the growing population, the government must make major investments in projects to bring water in from outside the valley." As for air pollution, Mr. Menendez says improvements are already evident. He pulls out a chart showing lead, nitrogen oxide, carbon monoxide, and sulfur dioxide at, or below, federal norms. Ecologists agree the levels of some contaminants are coming down. But they note that city figures are averages taken from many locations, thereby masking dangerous levels. Environmentalists say more drastic measures are needed. Higher gas prices, blocking the city center to bicycles only, two days without car or a day without industry are often mentioned as possibilities.