The smouldering embers at Dalgoan Tea Estate in West Bengal are dying down, but they have once again stoked the perennial resentment of tea growers -- labour trouble.

As business circles and political quarters dissect Thursday's incident in which 21 tea gardens workers were burnt to death, industry officials are at one that the massacre was yet another pointer to the malaise of irresponsible trade unionism.

"Incidents such as these will affect the industry that is already struggling with falling prices for four years," says R S Jhawar of Williamson Magor.

On Thursday morning, a mob of around 1,000 workers torched the house of their union leader, trapping 21 people inside the blaze.

But, why did the workers turn against their leader?

Police's preliminary investigation says union leader Tarakeswar Lohar had sold out three jobs of clerks for the estate to outsiders when there were eligible local candidates.

Angry workers questioned him, but the altercation flared, leaving behind a tragic consequence.

"This is such a classic example of irresponsible trade unionism for which the industry suffers," says an official of Indian Tea Association. The result is that production is affected and the work environment is vitiated.

Labour trouble is said to be the reason for closure of around 30 tea estates in West Bengal, 16 of them in Jalpaiguri district alone, where Dalgoan Tea Estate is situated.

The state's leftist government claims that garden owners always try to shortchange the workers. The companies say the workers are belligerent and are always arm-twisting the management.

The government says Dalgaon was an isolated incident, but the industry claims that the Marxist-backed trade union, CITU, has been creating problems regularly.

It can be a mere coincidence that Lohar was the leader of CITU-backed Cha Bagan Mazdoor Union at Dalgoan.

Can it be a coincidence as well that most of the closed tea gardens in West Bengal had CITU-backed unions in power?

Violence breaks out with alarming regularity in the tea gardens of northern Bengal. There have been at least six recorded incidents of violence this year, including the murder of a factory assistant in Chengmari tea estate by irate workers.

A few years ago, 13 people were killed in a clash between rival groups of workers at Red Bank tea garden near Dalgaon estate.

Industrial violence, however, is much more widespread in the state's tottering jute sector in which workers assault and even kill management staff.

"What happened in Dalgaon is not political. We are inquiring to find out what happened," says state Chief Minister Buddhadeb Bhattacharya.

"The incident was a law and order problem, nothing to do with industrial relations," said A K Motilal, secretary of the state-run Tea Board.

But, the assurance of inquiry will mean little to the proprietor of Dalgaon estate who is losing out on production at the end of the tea-growing season.

India's tea exports have declined by 28.34 percent to 71.54-million kg this fiscal from 99.83-million kg in the corresponding period last year. Price realisation of exports is also down this year.