But one thing India has not seriously tried could make the most difference: curtailing the fires set to rice fields by hundreds of thousands of farmers in the nearby states of Punjab and Haryana, where much of the nation’s wheat and rice is grown.

Although environmental court – the National Green Tribunal - told the government last year to stop farmers from burning the straw left over from their rice harvests, Nasa satellite images in recent weeks have shown virtually no abatement. Farmers are continuing to burn most of the leftover straw — an estimated 32 million tonnes — to make room to plant their winter wheat crop.

While fireworks associated with the Diwali holidays were blamed for a particularly bad smog problem in recent days, smoke from the crop fires blowing across the northern plains into New Delhi accounts for about one-quarter of the most dangerous air pollution in the winter months. In the growing metropolis of nearly 20 million people, pollution soared well above hazardous levels in the past week.

Farmers 100 miles north in Punjab were well aware that they were contaminating the capital’s air, they said in interviews, and were willing to consider other ways to dispose of the excess straw, but could not afford the options offered by the government. “We are smart, and we have adopted new technology in the past,” said Jaswant Singh, 53, as he watched a fire sweep across a 20-acre field near his village, Maulviwala, about 140 miles northwest of New Delhi.

He planned to set his own 7 1/2-acre rice paddy ablaze in a couple of days, he said, “because we can’t afford to pay for the new technology ourselves.” The air was thick with smoke that evening as I drove the two hours back to Punjab’s capital, Chandigarh, after spending several hours with Singh and other farmers. The smoke made it hard to see, slowing traffic to a crawl, and breathing was difficult. My lungs hurt with each breath, even though I have never had respiratory problems.

The smoke rising from the fires visible on farms on either side of the road would most likely reach Delhi in another week, depending on the wind’s strength and direction. Farmers began burning their fields two weeks ago, and levels of the smallest particles, called PM 2.5 and believed to pose the greatest health risk, were already soaring.

On Monday night, levels of these particles in one Delhi neighbourhood reached 688 micrograms per cubic metre, more than 10 times the healthy limit set by the Union government, the Delhi Pollution Control Committee’s website said. In every neighbourhood where air quality data was available, particle levels were at least four times the limit, putting most areas in the hazardous range by Indian standards, which are more lenient than those set by the World Health Organisation.

Asked how they could keep burning their crop remnants knowing they were causing health problems in New Delhi, Singh and other farmers said they were deeply concerned, especially because their families also suffered from the ill effects of the smoke. But still, they said, they could not afford to dispose of the material any other way.

In theory, as is often the case in India, it should be relatively easy to stop the burning. The government is promoting a seeder that can be mounted on a tractor and used to plant wheat without the need to dispose of the straw left after the rice harvest.

But Singh and others I spoke to said they could not afford the $1,900 cost of the most widely available brand, Happy Seeder. That is as much as some farmers earn from their entire rice harvest, they said. And they are reluctant to incur more debt, having already taken out loans for their daughters’ marriages and past equipment purchases.

To encourage farmers to use the seeders, the government is offering to pay half the cost. Yet it has money for only a tiny fraction of the farmers, said Bhure Lal, chairman of the Environmental Pollution (Prevention and Control) Authority, which was set up by the Supreme Court of India in 1998. Another alternative to crop burning, Lal and the farmers said, would be to create a market for the excess straw. So far, seven power plants that generate electricity from straw have been built in Punjab, and six more are on the drawing board.

Lacking in will

But together, all 13 would consume only 1.5 million of the 20 million tonnes of straw produced in Punjab every year, or less than 10%, said PolashMukerjee, a researcher at the Centre for Science and Environment, a New Delhi research and advocacy group, who also assists Lal’s environmental authority. That is not enough to create a market for the straw, so it would still cost farmers far more to gather it and bring it to the plant than to burn it in their fields.

“If the government paid me for my straw, I’d stop burning it today,” said Shabaz Singh, 32, who grows 25 acres of rice and wheat in Maulviwala. The burning of crops was outlawed some time ago. But, like many laws in India, it is widely ignored.

Certainly, none of the farmers feared being hit with fines that are supposed to range from $38 to $225. “If the government wants to stop it, it can stop it,” said Harjinder Singh, a father of two school-age children from Duttal village, who was the only farmer I met on my visit who said he did not intend to burn his crop. “But the government lacks the will to do so.”

Singh and his brother, Narinder Singh, 38, were riding on a tractor pulling the Happy Seeder device when I stopped by their 12-acre farm last week. They used a government subsidy to cover half of the cost of the device, and paid about $950 themselves. It has worked well for them in the three years since they bought it, the brothers said. Not only did they avoid burning their straw, they said, but their yields of both wheat and rice went up, suggesting that leaving the straw on the ground instead of burning it was improving the fertility of the soil.

Mukerjee said he believed many more farmers would adopt the Happy Seeder machines if the government made subsidies more widely available. But so far, neither the Central nor the state governments have committed the money, he and Lal said.

The Punjab government told Lal’s environmental authority that providing all Punjab farmers with Happy Seeder machines would cost about $1.5 billion. “In real terms, the government hasn’t created any alternatives for the farmers,” Mukerjee said.