'When I started this farm, people told me I was crazy,' said Mr Langbour. Fourteen years later, business is booming and demand growing fast, he said: he sells his produce to five-star hotels around the country as well as to individual customers.

'There's so much money for this kind of thing in India today,' he said, waving towards a cage of frantic looking ducks that are waiting to 'go to market'.

Few farmers in India, where 70 per cent of the billion-plus population are dependent on agriculture, can speak with such confidence. Farming in India is in the doldrums. Annual growth is about 2 per cent, compared with the economy's much celebrated 9 per cent.

The failures of many farms of less than a hectare, which mostly make up the sector, have prompted the government to push for the development of large-scale industrial farms. But a growing number of small establishments that farm organically - a system that does not allow the use of pesticides, chemical fertilisers and genetically modified crops - are bucking the trend, demonstrating that it is possible to make a living from more expensive, specialised products.

Last year, certified organic land under cultivation in India rose 40 per cent, from 2.5 million hectares the previous year. Most of this growth is driven by exports - mostly of honey, tea, spices and rice to Europe - which increased by 20 per cent to 1.8 billion rupees (HK$343 million) in the past year. The Agricultural and Processed Food Products Export Development Authority of India, which oversees the organics market, expects exports to grow by 50 per cent and more.

The domestic market, too, although much smaller, is growing fast. Kanu Somany, who lives on a farm near Gurgaon, began growing organic lettuce for her family because she found it difficult to wash fragile salad vegetables properly, 'and you want to get the pesticides off them'.

Within months, she was supplying lettuce to her friends and wider family; soon she started selling them to a wider circle of acquaintances; today, she makes a weekly delivery to 500 families in and around the capital. 'It's mostly people with children, who want to eat healthily,' she said. 'Interest in pesticide-free produce in India is definitely growing.'

Health-conscious Indians perhaps have more reason to go organic than many.

In India, farmers' dependency on pesticides over the years has led to dangerously high levels of toxins making their way into everyday foods. Recent tests by the Ministry of Agriculture on samples of fruit and vegetables in a Delhi market found produce contained 30 to 50 per cent more than the country's permitted levels of pesticides and heavy metals.

Most Indians, however, cannot afford to worry about such matters. Because organic is labour-intensive and expensive in other ways - involving costly inputs such as bio-pesticides, manure and bio-fertilisers - prices tend to be 25-30 per cent higher than for non-organic produce.

Still, India's breakneck economic growth has produced a growing class of prosperous and discerning consumers - meaning there is considerable room for growth in the home market.

Twenty years ago, Ganesh and Jayashree Eashwar left corporate jobs in Bangalore, in the south Indian state of Karnataka, and bought a farm. They started selling their produce in the city and, four years ago, expanded to Delhi, where they opened a shop, Dubdengreen, that sells organic produce sourced from all over the country.

'When we first opened, our customers were mostly expatriates and a few Indians,' said Ms Eashwar, sorting through small bags of colourful, freshly ground spices in her shop, the biggest such walk-in establishment in Delhi. 'Now it is the other way round. There are more Indians than expats and a lot of them are young.'

She admits, however, that the vast majority comes from the privileged classes.

For some, the organic movement is more than a business opportunity. Dr Vandana Shiva, a Delhi scientist, would like organic farming in India to expand beyond a niche market for the health-conscious wealthy.

Two decades ago - well ahead of the curve - she set up Navdanya, a non-governmental organisation that has taught 3,000 rural small-scale farmers to return to traditional organic methods of farming.

'So much of the soil in India has lost its productivity because of too many chemicals and there are no nutrients left,' said Dr Shiva, a passionate advocate of organic farming.

'So farmers keep adding more and more and most are unaware of the damage it causes to human health, animal health and to the environment.'

Her organisation does not export its produce, even though this is where the big money is, 'because I was committed to changing the way India does things', she said.

Instead, Navdanya sells its farmer's produce from six outlets throughout India. 'In the early days, middle-class women would ask, 'What's wrong with chemicals?'' Dr Shiva said. 'That doesn't happen so much any more.'

She said organic farming - if implemented properly, with the rights skills and knowledge - could bring the nation's farming sector back to life.

Usha Tuteja, an agricultural economist at the University of Delhi, agreed, 'but only if organic yields could be raised. Poor farmers need to produce as much as they can and for that, the obvious answer is to use chemicals.'

There is a growing acceptance, however, that the overuse of chemical fertilisers and pesticides may lower yields in the longer term.

For years environmentalists have argued that the heavy use of such chemicals is unsustainable. But today, this thinking is having an influence on more mainstream thinking about India's agricultural future.

Forty years ago, India's Green Revolution - the widespread planting of a hybrid strain of wheat, plus greater use of fertilisation, irrigation and pesticides - helped the nation shake off recurrent famine and food shortages that had left it dependent on foreign aid.

Advocates of organic farming said the Green Revolution also left farmers over-dependent on pesticides, or 'ecological narcotics' as organic advocates sometimes call them.

Now, production gains in India are slowing as the water supply dwindles, excessive use of fertiliser and pesticides have poisoned the soil, and excessive irrigation has flooded the land along canals in Punjab and Haryana - showpiece states of the Green Revolution.

The man hailed as the father of that revolution, plant geneticist Monkombu Swaminathan, is calling for another big shift in Indian farming methods. The Evergreen Revolution, as he called it, aims to boost agricultural productivity without making excessive use of chemicals that damage the environment.

For the organic purists, however, there is only one way to go - even though it can be hard work.

Lakshmi Tripati took over her father-in-law's farm near Varanasi in the northern state of Uttar Pradesh three years ago. Here, she cultivates organic crops on 120 hectares.

The biggest job, she said, was getting organic produce certified for the export market. It would be three years before her land received the stamp of approval from an international certification body, she said, at which point she could start selling overseas. The domestic market remained tiny outside the big cities, she said. 'There is so much marketing we need to do.'

Ms Tripati is also bothered by the fact that many farmers - or, as is more likely, the business people who buy from them - have started slapping the organic label on produce that is anything but. 'No one checks up on you in India,' she said.

Still, she expected the sector to keep growing as a new generation of farmers discovers the business benefits of farming naturally.

'I tried for years to get my father-in-law to move away from conventional farming methods and he didn't listen,' she said. 'But, for me, I never wanted to do anything else.'