Mexico City would like to clear the air: it has made significant progress on cleaning up the atmospheric pollution that earned it an unsavory reputation as one of the world’s dirtiest cities.

It wasn’t long ago that a cloud of brown smog clung to the skyline and obliterated views of the snow-capped volcanos that overlook the city, but a 20-year cleanup campaign has resulted in unusually good air quality, revealing picture-perfect vistas that extend miles into the distance.

"In recent years we have beat the records for most days with passable ozone readings. In 2009 there were 185 in the acceptable range and we have started out 2010 with the greatest number of clean days, 50 out of the first 60," Martha Delgado of the Mexico City environment office told AFP.

Poor air quality in the 1980s and 1990s incited millions of residents to flee the city for suburbs and other areas of the country and prompted city officials to limit the number of cars allowed on city streets. The city also modernized its public transportation systems, including a fast-lane bus program.

These efforts have had a remarkable effect, but smog-dispersing winds have also played a role and the city is still far from its goal of just one day a year outside healthy ozone limits, according to researcher Aaron Jazcilevich of the National University’s Atmospheric Science Center.

"It is possible that we may no longer be in the worst five,” said Jazcilevich.