Let there be less light

Govind Singh, director, Delhi Greens, an NGO, and PhD scholar, environmental department, University of Delhi, says, “Light pollution is an aspect of Deepawali that often goes unnoticed." For centuries, diyas (oil lamps) were the only lights set up on Diwali. These were also kinder to other living things. Now, these range from candles to electric garlands of fairy lights (“tuni" lamps), strings of electric bulbs and even harsh spotlights. Many of these are strung on, or near, trees and plants.

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Says Mumbai-based Deepa Katyal Engineer, veterinarian and trustee, People for Animals, an animal welfare non-profit, “Can you imagine how hot it must be getting for the tree and for the creatures living in it?" Harsh lights also disorient nocturnal creatures such as bats and owls. Daylight-loving birds, too, can’t sleep. The diurnal cycle of plants is disturbed too.

Don’t fan the flames

Both lighting and fireworks can damage plants. Ajay Mahajan, founder member of the Pune-based environmental organization Kalpavriksh, has seen many plants getting scorched during Diwali. “Plants register the presence or proximity to fire and they actually try to move away from the source of fire," he says.

Since Diwali comes at the end of the peak growing season for most plants, leaf burn can set the plant back by months. Plus, if you peg fireworks to a tree, it injures the inner bark, a living part of the tree. “That’s where the nutrients and water move," says Mahajan. “Stop treating trees like lamp posts or an inanimate trellis." Fireworks performing aerial pyrotechnics can also singe insects, birds and arboreal animals such as squirrels.

Don’t raise a stink

Then there’s the more palpable air pollution. During Diwali, most of us are thankful for the plants, those great carbon sinks. They take in a lot of air pollution at a terrible price. Few new leaves sprout and existing leaves get caked with pollution. “I have noticed a black liquid drip from leaves around this time from pollution," says Mahajan. “Unlike dust that just sits on the leaf, this sticks to it. It is also tougher to wash off."

Fire crackers are made of potassium nitrate, sulphur and charcoal. When burnt, noxious fumes are released, including sulphur dioxide, carbon monoxide and carbon dioxide. These gases irritate the air passage of humans and animals. “If higher species like humans and dogs get respiratory allergies due to the pollution caused by crackers, do insects and birds stand a chance?" asks Dr Katyal Engineer.

In plants, these harmful chemicals are absorbed through the stomata (pores) and choke them. Vidya Subramanian, project manager, Delhi Greens, says, “Particulate matter like cement dust, magnesium dust and carbon soot on trees can inhibit the normal respiration and photosynthesis mechanisms within the leaf." With the stomata choked, plants can’t breathe or feed. This can also lead to the death of the leaf tissue.

What doesn’t coat or choke the leaves falls on the soil or floats in the air. If there is rainfall soon after Diwali, this pollution may come down as acid rain, corroding plants, altering soil composition and upsetting water ecosystems. Says Mahajan, “We don’t much look at soil contamination, although it is much more difficult to rectify than air or water pollution." If animals ingest the chemicals in fire crackers, these poison them.

Too big a bang

Animals, especially birds, are affected more than humans by the noise pollution. Says Dr Katyal Engineer: “The average animal has better hearing than humans. Dogs can hear seven times louder than humans. So if the fire cracker burst during Diwali deafens you, you can imagine its effect on them." Often, they flee, which is why it’s common for pets to get lost during Diwali.

All in all, your Diwali celebration makes for a less than bright outlook for the neighbourhood’s flora and fauna.

The author is a journalist and writer of children’s books, with a passion for gardening.

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