The two types of chocolate bombs and dodoma, which had been cleared after noise tests by the state pollution control board and police to determine the legality of crackers, have been banned again.

"All crackers banned till last year, including chocolate bombs and dodoma, will remain banned this year," said environment minister Sovan Chatterjee on Thursday in a meeting at the state PCB.

"I have taken the decision after discussing the matter with police as well as the highest leadership. I do not know about the measurements but I feel that we should not undo the good work that has happened over the years and has been accepted by people at large," Chatterjee told Metro.

Since 1997, all types of chocolate bombs and dodoma had consistently been found to emit noise beyond the permissible limit (90 decibel at 5m from the point where the cracker is burst). But this year, two variants of the chocolate bomb and dodoma had been cleared after tests. The decision was criticised and the test procedure questioned by the green lobby. Metro had reported the matter on October 19.

"I was told that these items produced noise just below 90 decibel. But there is always a possibility of other samples of the crackers producing louder noise. Neither the PCB chairman nor the principal secretary knew about the clearance. Only some junior officials were involved," said Chatterjee.

What made the reimposition of the ban easier was that the samples tested were found to have been manufactured in units that do not have PCB or explosive department clearance. "While one of the companies never had PCB clearance, the other's clearance had expired in 2006," said a PCB official. "We did not know that the items were from illegal units. The PCB should have warned us," said a police officer. PCB chairman Kalyan Rudra told Metro that PCB had only tested the items brought by police.