Today, and not for the first time this week according to the AirVisual app on my phone, Chiang Mai has the most polluted air of any city in the world. By a mile.

Here is the view from our window:

And here is the report for the sub-station closest to us:

The main figure, 329, is on a scale of 500 measuring overall air quality; anything above 300, according to the United States Environmental Protection Agency, constitutes “emergency conditions…the entire population is…likely to be affected by serious health effects.”

The PM2.5 figure (278.8) measures microscopic particles smaller than 3% the width of a human hair. These are so tiny that the normal dust-blocking mechanisms of the human nose and throat can’t stop them; they go straight into the lungs, and so into the blood. Completely safe levels for PM2.5 are considered to be up to 12; for levels over 250 the EPA warns, in the short term, of “serious aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly; serious risk of respiratory effects in general population.” We are cautioned to “avoid any outdoor exertion; people with respiratory or heart disease, the elderly and children should remain indoors.” In the long term, studies have found, PM2.5s can cause hardening of the arteries (hence increased risk of heart attack and stroke), and lung cancer.

This year is worse than most, but it happens every February and March: why? It’s tempting to lump it in with all the other ecological calamities of modern industrial civilization, but actually this is a really low-tech phenomenon: the country is burning. Part of it is accidental, but most is probably agricultural arson: burning rice stubble before planting again, burning forests to clear fresh land for planting, and even (it is said) burning underbrush to stimulate the growth of rare mushrooms which fetch a lot of money. Information about how long these farming techniques have been used is hard to find, but the only particular connection I can see with the 21^st century is that there are more of us than there used to be – more mouths to feed, and so more encroachment on the forests.

So what is being done to stop it? In a nutshell, nothing. There have been tales of governments and NGOs providing tractors to farmers so that they don’t need to burn, but how many tractors would you need in an area the size of northern Thailand? There is even nominally a burning ban throughout March and April, but again, how do you enforce that effectively across such a huge area, even if there is the will to do so? Which, apart from a few show operations, there doesn’t seem to be: after all, the enforcement officers are often in the same communities, and may even be related to, the farmers who see no other way to maintain their crop cycles. On top of which, the level of burning is actually way less in Thailand than it is in neighboring countries like Burma and Laos, where there is lower awareness and even less effective government; and smoke is no respecter of national borders. Some of it may be coming from as far away as south China, where the government really is concerned about air pollution – but in Yunnan, the closest Chinese province to us, there is a saying that the hills are high and the Emperor is far away…

In response, some of the schools here are shut. Others (including our kids’ place) argue, correctly, that while parents are free to keep their children at home if they wish, schools have air filters in classrooms, all exercise is cancelled, students are told to stay inside and, when they do have to venture outdoors, wear masks; so they may be safer at school than in homes which don’t have proper air filtration (that includes ours – we could buy a bunch of air filters at $150 apiece, but then our windows aren’t sufficiently well-sealed that it would make all that much difference).

Me, I’m barely moving a muscle. Especially since this has now been going on for the best part of a week, and may continue for another month or more, until – we hope – the first seasonal rains arrive to put out the fires and wash the smoke to earth. Mildly streaming nose, slightly sore throat, low-level headache, gentle wheezing in the lungs, all of these are in a day’s sitting as still as possible. All this, it is said, adds up to the equivalent of smoking a couple of cigarettes a day. So I’ve put myself through far worse; but what’s more striking is the moodscape: the sense of living in a vast, inescapable, all-enveloping ecological catastrophe, land and sky alike permeated with smoke like the shadow that creeps out over the lands of the world as dark power crescendoes in Tolkien’s Lord of the Rings. Somewhere just over the horizon, it’s easy to believe, the world is ending in fire.