kolkata the smaller the idol the greater the risk of water pollution said environmentalists by a conservative estimate more than 20000 vishwakarma idols are immersed in the ganges and different tanks but the promptness of civic bodies to recover the structures which is witnessed after immersion of durga and kali idols is absent in case of other smaller pujas it is impossible to track the number of pujas like vishwakarma or saraswati but if you assess the impact the immersion of a 100 times higher number of smaller idols compared to those of durga puja or kali puja leads to more pollution said naba dutta general secretary sauj manchathe biggest concern is the presence of heavy metals in the paint on idols which enters the body through the food chain some like lead mercury zinc oxide and chromium are potent carcinogens said sudipta bhattachary of saviour and friends of environment who conducted a study on postimmersion water quality lead and chromium are toxic to humans even in very small quantities idol immersion poisons the waters by increasing acidity and can damage the ecosystem said somendra mohan ghosh an environmental activistnational mission for clean ganga banned immersion in the ganges and imposed a fine of rs 50000 for violation adequate arrangements should be made for designated immersion sites within the municipal area or bank of ganges and its tributaries by constructing temporary confined ponds with removable synthetic liners at the bottom however nothing is followed in reality said subhas datta an environmental crusader