Even as we go to press the bright lights are gone from the bazaars. With the Puja , Dussehra and Diwali sales and the holidays over and hundreds of thousands of idols of the goddess have been immersed in the nearest river or lake. This is where all idols go after the puja is over. The same rites have been carried out earlier during Ganesh chaturthi and the story will be repeated when it comes to Diwali . The small idols of Ganesha and Laxmi will be dropped into the nearest water body.

There was a time when idols were painted in natural colours, made from flowers and vegetable dyes. Of late, this practice has been consigned to the past. Today, paints laced with heavy metals and carcinogens have become common place. The state of the water bodies in which these idols are to be immersed is not hard to imagine. The idols themselves are no threat but the paints used are.

It was Bal Gangadhar Tilak who revived the festival of Ganesh chaturthi in Maharashtra. Thousands of idols of Ganesha are immersed every year in Maharashtra's rivers and lakes. But this year in Kohlapur things were different. Fed up with the pollution of the lake the people decided to change things. Hundreds of idols were collected and taken to a huge plot where they were broken up and the pieces dispersed on land. A way to save the lake and a way to carry on with the festivities was found.

We could go a step further. Rather than immerse idols in water we could dispose of them on land as a rule every where. It would be better still if idolmakers reverted to tradition and began to use vegetable dyes and natural colours rather than synthetic paint full of toxins. Otherwise, the rivers that Hindus worship may be poisoned by the idols they worship. It would be best to act immediately lest our idols develop feet of clay. It is hard to say what causes this but Speakman suspects that competition is the main factor. Although at present sand martinis are too small in number to offer much competition, following their population crash in the 1980s, he suspects that the bats' continued nocturnal habit reflects "the ghost of competition past' ( New Scientist , Vol 163, No 2205).