An Indian farm group said its members had planted a variety of genetically modified cotton seeds which have not been approved by the country's government, an offence that could result in five years imprisonment.
It is the first time farmers, who argue that they shouldn't be deprived of any new technology, have acknowledged planting the herbicide-tolerant cotton variety, which was developed by German drugmaker Bayer AG's Monsanto unit.
Industry officials estimate the area planted with such seeds reached at least 10 percent of the 12.2 million hectares of Indian cotton acreage in 2018 and Anil Ghanwat, president of the Shetkari Sangathana farmers union, said there is likely to be an increase this year.
"Until last year, farmers were cultivating the unapproved seeds covertly. From this year, we will plant them publicly," Ghanwat said.
"This is a civil disobedience movement to highlight oppressive government laws," he added.
A spokesman for Bayer said cultivation of unapproved technologies without following mandatory guidelines would set a bad precedent and would be akin to dismantling the country's robust regulatory process.
India approved the use of genetically modified (GM) cotton seeds in 2002 and an upgraded variety in 2006, helping transform the country into the world's top producer and second-largest exporter of the fiber.
However, Monsanto withdrew an application seeking approval for the latest variety after a royalty dispute with the government in 2016.
The herbicide-tolerant variety, which helps farmers reduce weed management costs, has seeped into Indian agriculture anyway, boosting sales of glyphosate-based weedkillers, which environmental activists say could spoil local biodiversity.
Lalit Bahale, a farmer from Akola district in Maharashtra state, planted the seeds during a public event on Monday organised by Shetkari Sangathana ahead of this year's cotton planting season, which lasts during the rainy months of June and July.
"I know the law, but still I broke as it is against farmers' rights," he said.
Under India's Environment Protection Act, farmers can be imprisoned for up to five years and fined 100,000 rupees ($1,436.99) for planting any unapproved seed variety.
Just before the 2017 harvest season, authorities found traces of the Monsanto seeds in the key cotton producing states of Maharashtra, Andhra Pradesh and Telangana.
The federal and state governments last year warned seed distributors and farmers against planting and selling the unapproved variety.