Populace boom strains Mexico City's resources. 40 to 50 million people by century's end means more traffic, smog, noise

About 14 miles from the edge of this giant city, Margarita Hern'andez has settled into a small cement-block house with no running water on an unpaved street. Like her neighbors, she buys water from a delivery truck and pirates electricity from a nearby power line. Her town is just one of a ring of towns mushrooming around Mexico City, with people moving there from the capital or from other parts of Mexico.

Already the world's most populated metropolitan area, Mexico City is expected to more than double in the next 14 years to at least 40 million people. The urban sprawl is expected to reach for 45 miles.

This means thicker traffic jams, more smog, and more noise. It also means more challenges to the ruling government party, the Institutional Revolutionary Party (PRI), which has run into some of its most serious opposition in recent years in urban areas, analysts say.

Like many Latin American nations, Mexico has seen a decline in its birthrates over the past two decades. But birthrates in urban areas in Mexico and many other Latin nations are growing about twice as fast as birthrates for the overall population, according to a recent study by the Population Reference Bureau in Washington.

``Problems stemming from rapid urban growth -- unemployment, urban poverty, slum housing, strains on urban services, and the political unrest these can generate -- are among the most pressing issues that the region faces . . ,'' says Thomas W. Merrick, author of the study.

If the capital area reaches the predicted 40 million level it will be ``unmanageable,'' Mexico City's chief planner Roberto Campa Cifrian told the Monitor.

Meanwhile, the demands on the government and the PRI from urban residents are increasing, says political and economic analyst Fern'andez L'opez Portillo Tostado.

People like Mrs. Hern'andez are seeking improved services: in her case, a paved road, water and sewer lines, and title to her land. Mr. L'opez says that in the current economic crisis, PRI is less able to respond to such needs.

The number of urban citizen groups springing up outside the PRI structure has been increasing in recent years, he says. They seek specific services -- for example, services for the young or the old. ``Before they asked, now they demand,'' L'opez says. Many of them not only oppose PRI, but oppose all political parties, he says.

Nearly a thousand people arrive here daily from other parts of Mexico, and another thousand are born here, says Gustavo Garza, director of the Center for Demographic and Urban Development Studies of Mexico College. He says between 40 million and 50 million people will be living in the Mexico City area by the year 2000.

Government efforts to date to move people out of the capital area are equivalent to a few week's worth of population increase here, Mr. Garza said in an interview.

Experts outside the government say government efforts to stem the flow of people here are having little effect. The government has taken increasingly strict measures to prevent squatters from moving into Mexico City. They are often physically prevented from moving onto the land or are moved out once settled. But on city outskirts, enforcement is more lax, Garza says.

Many of the poor newcomers move in with friends or relatives, says Francisco Alba, a population specialist at Mexico College. Many are never squatters, he says. He sees an eventual slowing of the urban growth rate as it becomes too unpleasant to live here and too time-consuming to do business here. He notes that Mexican birthrates have declined from about 3.5 percent per year in 1970 to about 2.2 percent today. He predicts a further decline to about 1 percent by the end of the century.

But the high percentage of working age Mexicans will not begin to decline in this century because of the previously high birthrates, Alba says.

Jobs and education are attracting people like Guillermo Salazar here. He moved here to complete his teacher training because he had been unable to find a school in his home in southern Mexico. Now he and his wife live in a one-room home built of packing crates on a small plot of ground he bought at the edge of the city. But he said that fewer of his friends are moving here now partially because there are now more schools back home.

Since President Miguel de la Madrid Hurtado's election in 1982, Mexico has doubled the amount it spends outside the capital area on such things as schools, roads, and other public services. But efforts to decentralize the government by moving part of the bureaucracy elsewhere have showed few results, Mexican officials say.

Government and private executives are reluctant to leave the capital because ``here is where they make all the decisions,'' L'opez says. With the severe inflation, professionals like himself are often taking more than one job (he has three) to keep up their standard of living. This is done most easily in the capital, he says.

Much of the southern part of the city is still undeveloped because it is a recharge area for aquifers supplying some of the city's water, Mr. Campa says.

To control and curtail undesired growth in the city, the government is limiting building permits and trying to enforce zoning density regulations. New enforcement personnel will begin checking trucks hauling building materials to see if related permits have been issued. But houses are still sometimes built illegally in cornfields and detected only after the harvest.