I did myself no favours at China's Bookworm Literary Festival in March when I announced on stage that Beijing was "the ugliest city I'd ever seen". Even the expats were offended. Yet the problem wasn't simply my typical tactlessness. After a few days of trudging through that dingy fug, as ranks of monotonous, cheaply constructed tower blocks foreshortened into the gloom, I didn't think I was venturing an opinion, but stating a self-evident fact.

Though I'm no China expert, there may be some modest value to the fresh eye. The native Chinese and expats alike had over-adapted to their dystopic town and could no longer see it.

The air? I'd read the news reports, and fancied I was prepared. I wasn't. The atmosphere was so thick and brown that I could taste it. This hard-to-pin-down flavour (imagine sucking on a nickel in one cheek and on a multivitamin in the other — mmm) coated the entire inside of my mouth with a greasy, toxic film, inducing a mild but persistent nausea. Unless you're treated to the rare, much celebrated "blue-sky day" — when the wind disperses the auto and factory emissions, coal smoke and the singe from rice paddies being burnt off for spring planting — the coffee-stain air leeches the vibrancy from colours, all of which become variations on beige. Walking around Beijing is like watching the world on 1970s TV.

Thus despite an impressive absence of litter, everything is filthy-covered in the same dingy film that coated my mouth. The facades of buildings are paled over with particulates, the creases of dilapidated window frames emphasised by grime. Dull and lifeless, public shrubbery looks plastic. The very trees are dirty.