Sky lanterns are small hot air balloons in which a small fire is suspended before releasing it into the open sky. (Agencies)
As it offers a visual treat and brightens up the night sky, such lanterns are getting increasingly popular in cities, especially during Diwali, the festival of lights.
Environmentalists have however, clarified that it is a hoax that sky lanterns are eco-friendly and safe to use as it causes pollution and litter besides being a serious fire hazard for properties.
"How can anything that burns and emits smoke be called eco-friendly? If people start replacing crackers with sky lanterns then it can be equally disastrous," Anumita Roychowdhury, head of air pollution control team at the Centre for Science and Environment (CSE), said.
To sell sky lanterns, a marketing company in Kolkata has started a campaign called 'Illumination' claiming these lamps are an eco-friendly way of celebrating Diwali as they light up the sky without causing noise pollution.
Green technologist Somendramohan Ghosh, who is an expert on air pollution, said besides polluting mid-air, sky lanterns are dangerous because naked fire is left out to float in the open sky.
"Large number of such lanterns may crash with each other in the sky if the wind velocity is over 20 km per hour. Or they can strike a high-rise building, a communication tower or even a low-flying aircraft," he said.
The activist warned that such events where large numbers of sky lanterns are released, fire service department permission should be mandatory for safety aspects.
When contacted, West Bengal Fire Services Additional Director General Gopal Krishna Bhattacharya said the organizers should take clearances from the fire department as it is very risky. A number of cases of fire by sky lanterns have been reported the world over.
In July this year, a massive fire in a plastic recycling plant in England was caused by a sky lantern resulting in a loss of an estimated six million pounds worth of damage.
Sky lanterns are already banned in most European countries, including Germany and Austria. In China, the practice is forbidden in the city of Sanya.
The litter left by sky lanterns is another issue as once the fire fizzles out the empty balloon will fall down on earth.
Although some manufacturers claim they use bio-degradable material but a small metal rod is hidden inside the lamp to hold wax.
"This can fall down anywhere - on streets, trees and even in water bodies. It will create a mess everywhere," CSE's Roychowdhury said. Besides the thin metal rod can even kill or injure birds, animals, livestock and marine life.
Sky lanterns are small hot air balloons in which a small fire is suspended before releasing it into the open sky.