New Delhi: Citizens of this city, who are taking up cudgels against the felling of their already diminishing stock of trees to make way for commercial and government residence buildings as part of a redevelopment project for the city, got some relief when the Delhi high court banned the cuttings till July 4.

Last weekend, over 1,500 people protested in the Sarojini Nagar area of south Delhi against the proposed cutting of over 14,000 trees for a project by the National Building Construction Corporation (NBCC).

Some likened Delhi’s protests to the famously peaceful protests in the 1970s, mainly by women, against the felling of trees and encroachment of forests in the part of Uttar Pradesh state today called Uttarakhand. The Delhi protests came amidst online petitions and a subsequent PIL filed by Mihir Garg and Rashi Jain at the Delhi high court earlier this month, against the Delhi government’s department of forests that initially granted permission to cut 16,500 trees (of which 11,000 are in Sarojini Nagar alone). There is also a petition pending in the National Green Tribunal, filed by an NGO called the Society for Protection of Culture, Heritage, Environment, Traditions & Promotion of National Awareness.

The roots of this issue lie in an approval granted by the Union cabinet in July 2016 for the ‘redevelopment’ of seven residential accommodation colonies to expand housing facilities under the ‘Master Plan 2021’ to cater to the city’s ever-growing population. The government said that the rationale behind the decision was the shortage of government accommodation, which led government officials to wait for eligible housing. So the ministry of urban development proposed

“redevelopment of existing old dilapidated housing colonies to augment the housing stock by making optimum utilisation of land resources as per Master Plan Delhi (MPD) – 2021, and using modern construction technology with green building norms and in-house solid/liquid waste management facilities.”

While the NBCC is to oversee the redevelopment of the Nauroji Nagar, Netaji Nagar and Sarojini Nagar colonies, the Central Public Works Department will administer the project in Kasturba Nagar, Mohammadpur, Srinivaspuri and Thyagraj Nagar. The foundation stone for the project in Nauroji Nagar was laid by Venkaiah Naidu, the vice-president, on May 17 and sanctioned Rs 32,835 crore, including for the construction for a ‘World Trade Centre’ in the area.

An online petition says that Delhi has witnessed “massive tree felling” over the last 10 years, with an estimated 15,000 trees cut between 2014 and 2017 alone. The Delhi Metro Rail Corporation had said in April 2015 that 46,529 trees had been cut to make way for the first three phases of the Delhi metro.

Rules set by India’s environment ministry stipulate that compensatory afforestation should follow any cutting of trees. The petition, however, pointed out that the “project’s proponent, the NBCC, has a poor track record in compensatory afforestation” and urged the citizens of Delhi to “speak up” for the trees instead. Compensatory afforestation has been suspect for long. As Kanchi Kohli, a researcher at the Centre for Policy Research, New Delhi, and her colleague wrote in The Hindu, the practice, “taken up in lieu of trees felled by projects, is a failure due to poor survival rates of saplings and no monitoring.”

Following the protests, Anoop Mittal, the NBCC chief managing director, told mediapersons on June 25, “Utmost care is being taken to protect the environment while redeveloping General Pool Residential Accommodation colonies in the national capital to utilise existing land resources in the most efficient manner and meet the growing demand for built-up space. Our vision is to develop Delhi in the most planned and sustainable manner and ensure apart from these colonies, sewage treatment services are also provided in neighbouring colonies.”

Kohli told The Wire that the project design was flawed at the outset because it wanted to cut trees instead of building upon existing infrastructure and redesigning them to accommodate the flora, keeping in mind the role trees play in mitigating Delhi’s obnoxious air pollution. She also said there has been no public disclosure of the number of trees that have already been cut in Delhi. And “even if this is not required by law, public disclosure is needed as part of good governance.”

During the press conference, Mittal provided some figures. He said that the NBCC had planted 4,722 trees of 64 varieties, including 896 fruit-bearing ones, since its redevelopment work at New Moti Bagh had concluded in 2012. He aded, “This year alone, 2,000 trees more trees are being planted.”

Similarly, in East Kidwai Nagar, Mittal said the NBCC had “saved” more than 30% of fully grown trees during construction work in 2014, and that the NBCC would plant 8,165 trees in the area while the city forest department would plant another 9,480 trees at other locations to maintain “ecological balance”.

However, conservation scientists and activists alike have pointed out that planting trees is not an end in itself. The samplings have to survive – not all do – and it takes years for survivors to grow to full-grown trees, C.R. Babu, professor emeritus at the department of environmental studies at the University of Delhi, pointed out.

He said, “Trees are very efficient scavengers of dust and pollutants,” and that several studies have shown that “wherever there is a high density of trees, the quantity of pollutants is drastically low. Conversely, the amount of dust trapped by the trees in these areas is very high.”

The protective effect of trees depends on the species, the type of canopy and the size of the tree’s leaves, Babu explained. Exotic species with smaller leaves, such as the common Prosopis juliflora, have little effect on reducing dust and pollutants, whereas broad-leaved trees do so quite efficiently.

Anumita Roychowdhury, head of the air pollution and clean transportation programme at the Centre for Science and Environment, New Delhi, agreed. “Trees and vegetation cover have a critical role as dust-stoppers, especially during summers, for Delhi and are absolutely essential as a green walling mechanism.”

So “the removal of such a large number of trees is not good for a city like Delhi, which is already considered one of the world’s most polluted cities,” Babu added.

Roychowdhury also remarked that the current issue shines the spotlight over how India’s cities are being built – such that the result is a pronounced ‘heat island’ effect. Because of this, India’s urban areas are considerably hotter than the surrounding rural ones. And heat islands don’t just mean higher city temperatures; they also produce more sulphur and nitrogen oxides, volatile organic compounds and ammonia. Recent research has also shown they disrupt local ecosystem balances and select for animals and insects with certain traits over others.

However, the existing vegetation stock and urban forests can offer some protection against such effects of heat islands. Apart from being a bulwark against dust and pollution, trees are also home to insects, birds and ground mammals, providing shade and nutrients, and support the growth of grasses around them. So, as Babu noted, when a tree is cut, all these things are lost. In addition, native trees also support a unique microbiome – microorganisms in a particular environment – that will be lost with their felling.

Scientists and environmentalists have also called for the redevelopment project to be redesigned to ensure no large-scale felling of trees has to happen. “There is a need to find urban design solutions where it is possible to protect the tree grid and build around it,” Roychowdhury said. “Construction agencies have to adopt sustainable methods and integrate them with new design principles, instead of continuing in a business-as-usual mode.”

Many of the trees slated to be cut are mature trees native to India. These are well-suited for Delhi’s arid climate as well as help maintain urban biodiversity, which makes them ecologically more important than ornamental trees favoured by horticulturists (e.g. frangipani, champa or palm species). Among the mature trees to be cut are species such as the banyan and fig trees (keystone species), semal and siris (both attract several native bird species when they flower), amla, guava and jamun. The Ashoka (Saraca asoca) and Arjuna trees (Terminalia arjuna) slated to be cut are important nesting sites for birds.

With inputs from Neha Sinha.

T.V. Padma is a freelance science journalist.