The many perils of decorative lights wrapped on Mumbai’s trees (2024)

Besides causing light pollution and affecting citizens, the decorative lights are also detrimental to the health of the trees and nocturnal animals.

Disruption of photosynthesis process and time clock in trees

Akin to the body’s circadian rhythm, plants follow a 12 hour day/night cycle.

According to experts and research, exposure of artificial light to plants throughout the day — thanks to the decorative lights wrapped around their barks and branches — affects their day cycle, and their ability to carry out photosynthesis, a process through which they convert light energy into chemical energy to fuel their activity.

Dilip Shenai, an ecologist and horticulturist, said, “In any plant, the consumption of sunlight happens during a 12 hour day cycle during which they perform photosynthesis.”

However, when the plants are provided with excess sunlight — in the form of artificial lights — throughout the day, this natural time clock gets disrupted.

“The natural process, of the stomata’s opening and closing, gets affected when artificial illumination falls on them. Since plants don’t technically understand what is natural and artificial, they will start absorbing any light throughout day and night,” explained Shenai, adding that this will impact their rhythm and productivity.

Even proximity to a streetlight — let alone lights mangled around the branches — were found to cause stress in plants which likely affected their physiological processes like photosynthesis, according to a research paper titled ‘Effect street light pollution on photosynthetic efficiency of different plants’.

Another research paper. ‘Artificial light at night as a new threat to pollination’ also finds that night light has “negative consequences for plant reproductive success.”

External injuries to plants

Meanwhile, Shenai pointed out that besides the illumination, plastic and other lighting material wrapped around the tree as well as the nails used to fix the lights also adversely affect the plants externally, causing them injuries.

“Besides the injury, the materials also release toxins in the trees. For instance, the nails put on the trees can rust over time and release toxins,” he told The Indian Express, adding that

experts have also raised alarms over increased possibilities of electrical hazards which can lead to a fire, perishing a healthy tree altogether.

Speaking to The Indian Express, Stalin D, environmentalist and director of NGO Vanshakti explained, “The current passing through electrical lines of lights can gradually even kill the plants.”

Threats to nocturnal birds and animals

For the birds that nest within the illuminated trees of the city, the light emanating from them is a disruption to their sleeping patterns.

“Think of the difficulties you face while sleeping with the lights of your room on,” is how activists demonstrate the disorientation posed to wildlife and birds.

Referring to the nocturnals, Vanshakti’s Stalin D added, “Nocturnal birds, who are active during the night, face the harshest difficulties. Normal activities such as hunting, which nocturnal animals like owls carry out during the night, get affected because the lights affect their natural vision.”

Furthermore, several research papers have found that light pollution also interferes with the movement of migratory bird species, with birds often colliding into walls and structures due to reflecting surfaces.

Why has the Bombay High Court now taken note of this issue?

The Bombay HC’s notice came following the hearing of a PIL by activist Rohit Manohar Joshi, which mentioned the ill effects of putting up artificial lights on trees and nocturnal organisms during festivities and other occasions.

Advocate Ronita Bhattacharya, for the petitioner, referred to a July 2019 circular issued by the Delhi government’s forest department which states that all the sign boards, names, advertisem*nts, electric wires, high tension cables or other damaging elements ought to be removed from the trees. The circular had been issued based on an order from the National Green Tribunal (NGT).

To support the plea, the petitioner added that Section 2 (C) of the Maharashtra (Urban Areas) Protection and Preservation of Trees Act, 1975, defines the phrase ‘to fell a tree’ as including burning, cutting, or in any way damaging a tree. Moreover, as per Section 8 of the said Act, restrictions are imposed on tree felling, which is subject to permission being granted by a tree officer/authority of the civic body.

Taking note of the pertinent questions of public interest raised by the PIL, the bench has now sought affidavits in reply from the state and the civic bodies within four weeks.