DELHI-WALLAHS expect a spike in pollution during the autumn festival of Diwali, which is famed for its exuberant fireworks. This year the city’s bad-air index did indeed shoot up during the night-time revelry. But then, as winds died, the air chilled, smoke from the burning of rice stubble in surrounding farmland drifted in and the city’s thick traffic resumed, the index failed to go down again.
Delhi’s annual average measure of PM2.5, a fine dust that is the most toxic component of its pollution, stands at 122 micrograms per cubic metre (µg/m³), about double Beijing’s annual average. On Diwali and ten succeeding days this year, Delhi’s air was clogged with averages of well over 500µg/m³, with peaks of up to 1,000µg/m³. The World Health Organisation (WHO) says the “safe” PM2.5 level is a mere 25µg/m³ over 24 hours.
Like miners drilling underground
With the city’s 20m sneezing inhabitants complaining of sore eyes, itchy throats, headaches and fatigue, one trade association estimated that 5-10% of employees across Delhi were calling in sick. Dense fog caused pile-ups on roads. A sudden surge in sales created queues outside shops selling face masks and air purifiers. Arvind Kejriwal, chief minister of the National Capital Territory, which contains most of the sprawling city, likened it to living in a gas chamber. Edward Avol, an American scientist who has studied the effects of vehicle exhaust on children, says that Delhi’s pollution is at “an occupational level of exposure”, meaning that it is as bad as that experienced by, say, miners using power tools in a closed space.
On November 6th the national and local governments sprang into belated action, closing schools and construction sites, sprinkling water on the streets to dampen dust and tightening controls on vehicle emissions. Both India’s supreme court and a national green tribunal, created to address environmental issues, weighed in with orders for more government action, including the implementation of a staged plan to deal more promptly with such spikes in pollution.
India’s capital is ostensibly run by Mr Kejriwal and his Aam Aadmi Party, a populist opposition group that trounced rivals in elections in 2015. But as Mr Kejriwal has discovered, his “government” exercises minimal clout. It does not have the same authority as those of India’s states and it is locked in a bitter test of wills with the national government, led by Narendra Modi, the prime minister. The national government in effect controls Delhi’s police and the municipal corporations that run city districts. It also appoints the city’s governor, who wields hefty powers of oversight over Mr Kejriwal’s administration.
The city government’s attempt earlier this year to impose an odd-even scheme to curb traffic proved popular with commuters, but failed to reduce pollution much, leading Mr Kejriwal’s opponents to dismiss it as a stunt. The chief minister contends that most of Delhi’s smog comes from agricultural burn-off. The implication is that the governments of the surrounding states, one of which is run by Mr Modi’s Bharatiya Janata party, are to blame for failing to stop the fires. But one minister in Mr Modi’s government insists that 80% of Delhi’s smog is home-produced, and another has declared that the real problem is “political pollution”.
For farmers in northern India there are few affordable alternatives to burning the prickly stubble left after harvesting rice. For decades, governments have shied away from stopping the annual burn-off for fear of alienating farmers. An outdated dread of food shortages also prompted them to encourage rice growing, by offering floor prices and subsidies, in preference to other crops.
The nastiest part of Delhi’s toxic cocktail, however, is probably the particulate matter spewed out by diesel engines, which the WHO deems carcinogenic. Here again, successive Indian governments have made things worse. Keen to keep voters such as commercial drivers and tractor- and pump-addicted farmers happy, they instructed state-owned fuel companies to sell diesel more cheaply than gasoline. This promoted a massive switch to diesel engines. Indian carmakers, riding behind such European promoters of “clean diesel” as Volkswagen, ploughed millions into new diesel-engine factories. In 2013 more than half the new cars sold in India were diesel-powered.
The authorities have not been entirely useless. A past government helpfully ordered that most of Delhi’s taxis and buses be converted to run on cleaner natural gas. Mr Modi’s government earlier this year announced a speeding-up of new emissions standards; by 2020 new cars must have much cleaner engines, and will be run on far cleaner fuel. And although diesel in India remains cheaper than petrol, the difference has narrowed enough to shrink diesel vehicles’ share of the market. But for the next few years, at least, residents of Delhi will be paying the price of previous policies with their health.
Just how high that price is, no one really knows. A study published in Delhi in 2008 estimated that 40% of residents had damaged lungs. Along with a range of other ill effects from pollution, they were five times more likely to suffer from chronic lung disease than other Indians, and four times more likely to have hypertension. More rigorous studies in other countries have shown marked increases in respiratory problems, cardiovascular disease and cancer tied directly to pollution levels, as well as serious and permanent damage to the health of children. Frighteningly, notes Mr Avol, those results were based on levels of pollution that are only one-fifth to one-tenth of what Delhi lives with.