MEXICO CITY (AP) -- North America's largest city had its cleanest year
                  of the decade in 1999, the government announced in newspaper
                  advertisements Sunday.

                  According to the city government, smog levels forced declaration of an
                  emergency only three times -- covering five days -- during the year. The best
                  previous year during the decade had been 1996, when there were 10
                  emergencies covering 34 days.

                  The worst occurred in 1991, when there were 27 emergencies covering 177
                  days.

                  Even so, ozone levels in Mexico City's air were considered "acceptable"
                  only 65 days during 1999, up from 37 in 1990.

                  The smog record has political implications because the leftist opposition
                  Democratic Revolution Party won the mayorship of Mexico City in 1997,
                  ending generations of control by the Institutional Revolutionary Party, or
                  PRI. The man who won the 1997 election, Cuauhtemoc Cardenas, is now
                  running for president.

                  The ad did not mention that Mexico City, with 9 million people, holds only
                  about half the population of the Valley of Mexico. The other cities and much
                  of the region's industries are within the State of Mexico, which is governed
                  by the PRI.

                  In full-page newspaper ads, the city government said pollution had been
                  reduced by putting more vapor traps on gasoline pumps, increasing industrial
                  and car inspections, stepped-up firefighting and by reforestation programs.

                  It said weather conditions were roughly equivalent to those in previous
                  years.

                    Copyright 2000 The Associated Press.