Calcutta, Oct. 24: The Mamata Banerjee government has decided to tweak a rule it had framed a year ago to allow more than 400 brick kilns operate across the state, prompting questions on the decision's impact on river embankments, highways, railways tracks and the environment.

"The state cabinet today decided to allow brick kilns to run their businesses if they are at least 50 metres from river embankments, highways, railway tracks, schools and hospitals. The earlier stipulation was of 100 metres," a minister said after a meeting in Nabanna this afternoon.

According to sources, the government decided to tweak the buffer zone after it realised that more than 4,500 people would lose their livelihood if the kilns were shut down.

Last year, the state government had issued a notification mentioning that no brick kiln would be allowed to operate if it was located within a radius of 100 metres of schools, colleges, hospitals, highways and river embankments.

The decision followed a guideline the Supreme Court had issued to save vital installations from being affected by brick kilns.

The apex court had directed all states to frame rules on brick kiln operations after complaints that they caused air pollution and soil erosion.

Following the directive, the Uttar Pradesh government, for instance, had notified that no brick kiln would be allowed within a radius of 1km from schools and hospitals. Similarly, no kiln would be allowed to operate within a radius of 300 metres from national or state highways.

"The majority of the states framed the buffer zones for different installations between 1km and 300 metres.... Bengal's previous buffer zone of 100 metres was considered to be the most flexible in the country. The new buffer zone of 50 metres is nothing but a joke," said a senior government official.

While erosion of soil leaves installations such as railway tracks and highways vulnerable because of the destabilisation of the base, air pollution caused by the kilns could leave many, including school and college students or patients, susceptible to lung diseases.

"This is the reason the apex court wanted to relocate the brick kilns to a safe distance. Though it did not mention what would be the buffer zone, it was expected that the states would set up a rule in consultation with environmental experts," an official said.

"After announcing its own buffer zone of 100 metres, the Bengal government found out that more than 400 of the 1,300-odd brick kilns across the state would be affected. So, it set a new buffer zone of 50 metres," the official added.

Officials said the state government had decided to bring brick kilns under the administrative control of the commerce and industry department from the irrigation department only to ensure that no questions are raised over the decision.

"The West Bengal minor mineral rules allow digging of soil outside a radius of 50 metres from vital installations.... Now, the inclusion of brick kilns under the jurisdiction of the industries department would allow the kilns dig soil just beyond a 50 metre radius," said a source.

A section of officials, however, said it would be tough for the state to evade legal hassles if anybody moved court against the decision.