Varanasi: Residents of Varanasi often refer to the city by another name – anandvan or ‘forest of bliss’ – hinting at the area that once might have been a mighty forest, full of lush groves and ponds. Not much is left of that legacy now, as urbanisation and population growth seal more and more land.
Varanasi lost around 75% of its water bodies in the last 200 years. Parks and gardens too are shrinking continuously in size or vanishing completely. As a result, it has become a dense city.
Dense cities are usually hotter than their non-urban surroundings, due to what is called the urban heat island effect.
Fueled by global warming, longer and hotter heat waves are hitting India year after year. These interlinked trends of urbanisation and climate change increasingly endanger the health of India´s urban populations, potentially even leading to death.
Also read: India Urgently Needs a Comprehensive Public Health Plan to Tackle Heatwaves
Since 2000, heat-related deaths in India have doubled. Official numbers reported by the government are probably an underestimation, with some studies suggesting ten times more deaths.
Since the heatwaves in India are expected to become worse in the future, urgent action is needed to save lives among the growing Indian urban population.
How urban vegetation can save lives
During research in Varanasi for a Yale University project, we found that urban water and vegetation zones directly contribute to cooling the environment.
As shown in the visualisation below, the cantonment area (cantt), the Banaras Locomotive Works (BLW), and the Banaras Hindu University (BHU) are the coolest areas in the city. This difference of around 10 degrees celsius in land surface temperature can be directly attributed to the trees and vegetation in those three government-managed areas.
Land Surface Temperature in Varanasi on June 6th, 2023. Visualisation by Dominik Juling.
In the case of an extreme heatwave, this temperature difference can make life and death. However, social factors also play a role in, for instance, who can afford air conditioning or which parts of a city receive reliable electricity to power electric cooling devices.
While the Uttar Pradesh administration acknowledges the effectiveness of green roofs in their heat wave action plan 2024, no major government-sponsored initiatives are in place to implement green roofs in the most vulnerable parts of cities. So how can residents protect themselves?
Why residents must plant trees on roof terraces
Since the hottest areas in Varanasi mostly offer almost no space to plant big trees on the ground, utilising all the flat rooftop terraces provides a solution.
Also read: What the Scorching Summer Does to Delhi’s Informal Workers
Putting plastic pots with small-to-mid-sized trees in every corner of the terrace can provide much-needed shade and moisture which will cool down the rooms underneath the roof. The more residents in an area adopt this relatively low-cost measure, the better the effect will be.
Other benefits include the air-purifying properties of trees and the provision of healthy food, for instance, with mango trees.
Community-based gatherings and sapling distribution campaigns by civil society organisations are an effective way to educate residents, especially those in vulnerable areas, about the dangers of heat and the benefits of greening their roofs.
Reviving anandvan in Varanasi, as for other cities, is urgently needed to protect urban residents.
Dominik Juling is a researcher at Yale University.