Redesign of seven south Delhi redevelopment projects to avoid tree cutting, following the government’s demand, is likely to save three times more trees in their original locations than the earlier designs, urban planners and architects tell The Hindu

Planners and architects are reducing parking slots as well as housing units, reclassifying green areas, incorporating innovative building designs and reverting to original street networks in order to comply with the government’s demand to redesign seven south Delhi redevelopment projects to avoid tree cutting.

The redesign is likely to save three times more trees in their original locations than the earlier designs, they said.

Seven Central government housing colonies are being redeveloped, replacing narrow tree-lined streets and small two-storey homes — many of which are in urgent need of repair — with modern apartments in 12-20-storey residential towers. The development of commercial spaces alongside is expected to pay for the project.

While the Central Public Works Department (CPWD) is responsible for the colonies at Kasturba Nagar, Thyagraj Nagar, Srinivaspuri and Mohammadpur, the NBCC is incharge of projects at Sarojini Nagar, Netaji Nagar and Nauroji Nagar. The original plans called for felling of almost 17,000 trees.

Widespread protests

Widespread citizen outrage and protests against felling of trees in June led the government to halt work, and order that the designs of the projects be reworked to avoid tree-cutting.

The redesign has been completed in some projects where initial drafts are ready for submission to the government, but is still ongoing in others. The Hindu spoke to several planners and architects involved in the redesign, and viewed maps and layouts for some projects.

However, the one colony where tree-cutting has already taken place — Nauroji Nagar — will not be redesigned substantially as it is being developed as a commercial rather than residential complex. In fact, construction work has already begun, with developers vowing not to cut any more trees — apart from the 1,100 trees already removed — and to replant trees once construction is complete.

In residential projects, the existing layout has a multitude of small plots divided by a criss-crossing network of narrow, tree-lined streets. Earlier designs for redevelopment called for this intricate street network to be wiped out.

Planners kept the existing main roads but treated the rest of the space as a clean slate on which they proposed a layout of open green spaces and residential towers with a footprint several orders of magnitude larger than the old plots. Obviously, this meant that trees lining the streets would have to be cut or moved.

Under the redesign, planners will stick to the old street network as far as possible, making it easier to retain trees. However, a more fragmented layout will also result in less wide open spaces.

“It is a more restrictive vision,” said an architect.

The total number of flats will also be reduced by 10%-15%. It has inspired some innovation in design, as many buildings will change from monolithic structures to more irregular, organic shapes to accommodate the trees that grow amidst them. Different vertical shapes are also being tried out, especially in commercial areas, said the architect.

Some buildings are being planned so that the floors above the level of tree cover jut outward in such a way that they do not block sunlight reaching the trees below.

The other major culprit with regard to tree-cutting was the government’s initial insistence that all parking must be underground, planners said. This will avoid the current situation of roads clogged by parked cars.

Delhi Master Plan

The government also insisted that parking requirements for redevelopment be calculated according to the Delhi Master Plan 2021’s Unified Building Bye-Laws (UBBL), which uses the area of a house as the base to calculate how many parking spots are required. An initial proposal to replace UBBL with government housing norms — which allot parking slots based on type of unit rather than area — was vetoed by the government. That proposal would have reduced required parking space by 30%.

For example, for the 10,600-odd flats originally proposed for the Sarojini Nagar project, more than 24,500 parking spots were required and the plan called for three levels of basement space to accommodate them.

“When you excavate for a three-tier parking, there is simply no possibility of keeping the trees,” explained one planner.

When asked to redesign, architects took several steps to mitigate the parking issue. Only some parking spaces will now be placed underground; others will use stilt parking and multilevel car parks are being built above ground as well. Podium slabs are also being built in open spaces, with the concrete cut out around tree trunks; below the slabs lies basement parking, while a thin layer of soil is planted with grass above. One of the uncertainties lies in whether these slabs can be counted as part of the required “green space” under government norms or not.

With all the changes, planners have been able to pare down the number of trees which will have to be removed to a fraction of the number needed in their earlier designs. Sarojini Nagar, for example, has more than 11,000 trees scattered across its area.

Under the earlier design, developers had got permission to cut or remove almost 8,000 trees. In the latest draft of the redesign, that will drop to no trees being cut and about 2,000 trees needing to be transplanted.