After years of being notoriously smoggy, authorities in Mexico City have started to get a handle on the problem. The smog - occasionally brutal for decades - comes from just over two million vehicles, in a city of over 20 million. That level of car ownership is impossibly 'green' by U.S. standards. The city is in a bowl, at 6,000 feet. What (relatively, for its size) little pollution there is tends to stick around. Emissions controls have made a vast difference over what I saw when I came here two years ago. The beater cars, taxis, and buses that used to drive around looking like they had a campfire burning in the trunk - are gone. Peseros - the half-size buses you can usually flag down to anywhere within a couple minutes - have mostly switched to natural gas. The city just started putting up shared bicycle stations, at a density that is positively unAmerican. In this megalopolis, the megahighways are less than half the width of I-5. There are cabs everywhere, 12 subway lines and two new BRT lines, and more of both being built. Only the wealthiest, furthest-flung neighborhoods are anything less than extremely walkable. Today, a work day, from the center of the city I can see both snow-covered volcanoes, Popocatepetl (whose shape, height, distance and apparent size from here make it uncannily resemble Mt. Rainier from Capitol Hill) and Ixtaccihuatl: not clearly, but I can see them. After Christmas there was a newspaper cover photo of both mountains against blue sky, headlined, 'A View From the Old Days', but this year we've been able to see that view at least half the time since. Gringos who use this presumed ecological disaster of a city (lovely for the most part, really - I'm not kidding!) as a whipping boy in order to feel complacent about Americans' pitiful efforts (if you can even call them that) at real city-building or sustainability will find their suppositions shattered by any contact with the reality of Ciudad Mexico.