By Subir Bhaumik
BBC correspondent in Calcutta
Nearly half a million tea labourers have started an indefinite strike in the Indian state of West Bengal.
Tea workers in West Bengal are demanding better wages
The strike has crippled work in the state's three hundred and fifty tea gardens, including those in the famous hill district of Darjeeling.
The labourers are demanding better wages and perks.
But managers insist that wages should be linked to productivity - a demand labour unions in the tea estates have said is unacceptable.
Tea companies say the strike will badly hit Bengal's tea industry. And if it spreads to neighbouring Assam, they say the entire Indian tea industry will be crippled because the two states account for nearly 85% of the country's total tea output.
P K Bhattacharya, a senior official with the Indian Tea Association (ITA), told the BBC that production losses could run into 100,000,000 rupees (£1.3m: $2.3m) per day.
He said there would be very little Bengal tea, particularly Darjeeling tea, on offer in the tea auction centres in eastern India.
The bosses of tea companies will be hard pressed to meet existing orders - or book fresh ones - unless a settlement is reached and the strike is called off.
Apart from closing down all work in the three hundred and fifty tea estates in northern Bengal, the labourers are planning road blockades on a highway that connects India's north eastern states with the rest of the country.
The tea labourers' unions say they will not accept the productivity-linked wages that the Indian Tea Association has suggested.
Union spokesman Samir Ray said they wanted the daily wage rate in Bengal to be doubled and other perks paid.
The ITA says the tea industry in Bengal - and also in Assam - is in crisis, with falling demand for Indian teas across the world, falling auction prices for teas and rising production costs.
But the labour unions say management has played up the crisis because it does not want to pay higher wages to the industry's half a million labourers.
Meanwhile, talks between trade unions representing tea labourers in Assam and the ITA have also fallen through.
Madhusudan Khandait, who heads the Assam Tea Labourers Union, told the BBC that the ITA's offer of productivity-linked wages were unacceptable because they will sharply divide the work force.
Mr Khandait said the union was also considering an indefinite strike in Assam's tea gardens if management did not accept their demands.