The use of artificial lighting affects Bengaluru badly. The city comes third, after Delhi and Kolkata, on a map tracking affected cities.
The rating is based on data collected by a group of researchers (see box) studying light pollution.
In 2016, the group had published a study that estimated that about 80 per cent of the world’s population lives in places polluted by artificial light.
The excessive use of artificial outdoor light has an adverse effect on the ecosystem. Life is conditioned by the varying lengths of day and night. Being in the sub-tropics, India is well placed to enjoy a balanced day-night ratio.
“Too much light, particularly with advertising and street lighting, interferes with public health and ecosystem functions,” says Leo Saldanha of Environment Support Group, Bengaluru.
Vijay Nishant, known as Bengaluru’s tree doctor, says the problem stems from ‘human arrogance.’
“We have occupied spaces without any concern, and without realising its far-reaching implications.”
As cities expand, light pollution grows. Places on the outskirts, such as Devanahalli, are now lit up, says Suresh Randadath, astronomer, environment conservationist and blogger.
LED lights, regarded as more polluting than other varieties, have become the only option, with incandescent lights completely disappearing from the market.
“Yes, they are energy-saving, but they are not good for the environment. Even if you don’t have an alternative, you do have the option of controlling your usage and relying on natural light,” he says.
What’s the big deal?
The effect of long-term exposure to bright artificial lights on sleep patterns has been discussed extensively. But its effect on the environment, not so much.
Light pollution can affect foraging, migration, reproduction and even survival among animals.
A study led by Brett Seymoure from America’s Colorado State University has called out light pollution as a detriment to insect life. Bengaluru is home to over 2,000 species of insects, and can no longer ignore the problem of night pollution. Nocturnal insects, such as moths, fireflies, are affected by light pollution.
“These creatures have always relied on natural light for navigation and while they may have adapted to some extent, artificial lights have disrupted things for them,” says Vijay. Dung beetles use the Milky Way to navigate and have been known to lose their way because of artificial lights.
According to the International Dark Sky Association, an organisation working towards combating light pollution since 1988, bees, butterflies, salmon, bats and owls are badly affected by light pollution.
Bats, which can be found in abundance in Bengaluru, forage during the dark. The bright lights make it impossible for them to recognise that it is night, affecting their eating patterns. Frogs and toads that sing their mating tunes in the dark find their breeding activities disrupted.
Artificial light can cause migratory birds to wander off course. Every year millions of birds die by colliding with needlessly illuminated buildings and towers.
Artificial lights can cause them to migrate too early or too late and miss ideal climate conditions for nesting, foraging and other behaviours.
“The nocturnal creatures are necessary for biodiversity to prevail. Human beings normally think of their own life and existence. But if light pollution disturbs millions of insects and other nocturnal birds, it will affect humans as well,” says Suresh Heblikar, founder of Eco-Watch.
The bright lights that envelope the nightscape has also taken away the option of enjoying the night sky from the city dwellers. “Now, you have to travel far out of the city to see a sky full of stars. As a result, less and less people are interested in it,” says Randadath.
It has also taken away the charm of the calming intent of the dark on the human mind, adds Saldanha.
Switch it off
It is not surprising for many that Bengaluru has fared as one of the worst affected cities in India. “It is the consumer capital of India. Appropriate lighting in public spaces during the night is essential to improve public security. But this needs to be done with nuance and care, to ensure light falls where it is needed, and not all over the place,” says Saldanha.
Unlike the other forms of pollution, the effect is not immediate, so it’s easy to ignore. “The effect will be slow, but solutions will take time as well,” says Randadath.
Sufficient, not excessive, lighting can be an outcome of regulation to ensure energy savings, thus reducing the contribution to climate change.
“All it takes is to be sensitive to the fact that there are other forms of life that need the darkness, as much as we do too,” says Saldanha.
* Rely on natural light as much as possible.
* Use focused instead of diffuse light.
The Light Pollution Map is based on the area affected. The online map was created by a group of researchers that includes Fabio Falchi, physicist working on light pollution for 25 years, Chris Elvidge, of the National Geophysical Data Center, Colarado, and Kimberly Baugh of the Cooperative Institute for Research in Environmental Sciences, Colarado.