BULANDSHAHR, India (AFP) — Across much of India, an energy crunch caused by the Iran war has prompted long queues for cooking gas cyclinders. That’s not a problem for Gauri Devi.

On a stove with blue flames, she flips a chapati flatbread, burning biogas produced from cow dung — an alternative fuel helping ease pressure on supplies.

“It cooks everything,” the 25-year-old said in her courtyard kitchen in Nekpur, a village in Uttar Pradesh, about 90 kilometers from New Delhi. “If the pressure goes down, we let it rest for half an hour and it works again.”

India consumes more than 30 million tons of liquefied petroleum gas (LPG) annually, importing over half its needs.

The government insists there is no shortage of cooking gas, but supply delays, panic buying and black marketeers have created long queues for cylinders.

However, since the 1980s India has also promoted biogas as a low-cost rural energy source, subsidizing more than five million “digester” units that convert farm waste into methane for cooking, and nitrogen-rich slurry for fertilizer.

For Gauri, it requires mixing a couple of buckets of dung with water, then pouring the mixture into a car-sized underground tank topped with a storage balloon.

It provides a piped methane supply so regular that she only uses an LPG cylinder for emergencies or large gatherings.

The biogas works for everything — “vegetables, tea, lentils,” she said.

The residual slurry is later spread on fields as fertilizer. It has better nitrogen availability for plants compared with raw dung, farmers say.

“The manure is so good,” said farmer Pramod Singh, who installed a larger unit in 2025, enough for six people, fueled by 30 to 45 kilograms of dung daily from four cows.

And he said the slurry fertilizer is particularly valuable at a time when global supplies of artificial fertilizers have been hit by trade disruptions due to the war.

“The real benefit is not just the gas — that is like a bonus,” local farmer leader Pritam Singh said. “The slurry is ‘black gold’.”

More than 45 percent of India’s 1.4 billion people rely on farming, and the country has one of the largest cattle populations.

India — the world’s most populous nation and third-largest fossil fuel polluter — has pushed large-scale biogas production to achieve a goal of carbon neutrality by 2070.

The government last year required that biogas account for at least one percent of liquid gas fuelling both vehicles and for domestic use -- rising to five percent by 2028.

Dozens of multi-million dollar production plants are now in the pipeline.

But small-scale rural producers are also being rolled out -- units cost around 25,000 to 30,000 rupees ($265-$318), often heavily subsidized by the government.

In a Hindu-majority nation where cows are revered and dung and urine are used in everything from floor plastering and fuel to ritual practices, it is easy to win supporters, said Pritam Singh.

He installed his first plant in 2007, and has helped put in 15 more in his village in the past year alone.

He said interest had shot up after the LPG shortages.

“People who earlier were not interested now ask how to get it,” he said.

“Once they see food being cooked and crops benefiting, they are convinced.”