Knowledge Nugget: Delhi’s ancient ridge is being restored— here’s why it matters

Key takeaways:

1. The Centre and Delhi government have resolved to develop 6,300 hectares of the Green Ridge area into forest land over the next four years and give legal protection to it to conserve its biodiversity, soil, water and Delhi’s environment.

2. The mega plantation programme includes plantation of 20.01 lakh trees, 37.07 lakh shrubs and 92,960 bamboo saplings, along with free distribution of 12.04 lakh saplings to schools, Resident Welfare Associations, institutions and citizens to encourage Jan Bhagidari in environmental conservation, according to officials.

3. According to the Delhi government document An Introduction to the Delhi Ridge, “a ridge is a geological aspect that features a continuous elevational crest for some distance. The Delhi Ridge is a northern extension of the old and ancient hill ranges of India called the ‘Aravalli Hill Ranges’, which extend from Gujarat through Rajasthan to Haryana–Delhi.”

4. The Master Plan of Delhi 2001 identified the Delhi ridge, which is divided into four zones: Northern, Central, South Central, and Southern. The position of different parts of the Ridge as provided by the Forest Department of the Government of NCT of Delhi:

(i) Northern Ridge: Northern Ridge, located near Delhi University, has an area of 87 ha.

(ii) Central Ridge: Central Ridge has an area of 864 ha.

(iii) South-Central Ridge: South-Central Ridge has an area of 626 ha, including Sanjay Van, and is located near Mehrauli.

(iv) Southern Ridge: The Southern Ridge has an area of approximately 6200 ha.

5. The Delhi Ridge is the tail-end of the city’s ancient Aravalli hill range and an ecologically critical zone. It works as a green lung for the capital and a natural barrier against hazards such as desertification and pollution.

6. In May, the Delhi government declared around 670 hectares of the Central Ridge — one of the Capital’s most important ecological zones — as a “reserved forest”. Authorities have also laid out plans to develop special vans (forests) and plant “native” tree species there.

7. The Central Ridge, however, was already a reserved forest, first notified in 1994 under Section 4 of the Indian Forest Act, 1927. Much like what happens with Protected Areas under the Wildlife Protection Act, a ‘first’ notification is meant to be followed by a settlement of rights, after which a ‘second’ notification under Section 20 of the Indian Forest Act, 1927, puts a final seal on the matter.

8. It has taken more than 30 years, but this second notification completes a process that needed to happen. A reserved forest notification gives the Forest department a firmer basis to regulate the area, prevent encroachment and take action against activities that damage forest land.

9. The Delhi government has announced that native and environmentally suitable tree species will be planted wherever suitable vacant land is available in Ridge areas declared as reserved forests. Neem, peepal, shisham, jamun, tamarind and mango are among the proposed species.

10. Separately, the Forest Department has also planned for the development of Special Vans – Tirthankara Van, Ritu Van, Rashi Van and Panchvati Van in Central Ridge under West Forest Division, which has been contested by environmentalists.

Analysis of tree species planted in Central Ridge

1. An analysis by The Indian Express of plantation records from the Delhi Forest and Wildlife Department, covering drives over the last four years in Central Ridge, shows that out of at least 22 species planted, only seven are characteristic Ridge species.

2. The Ridge of Delhi represents a tropical dry thorn forest characterized by the presence of scattered trees and thorny shrubs. The native plants exhibit xerophytic adaptations such as stunted growth, thorny appendages, wax-coated, succulent, and tomentose leaves.

3. Where the soil profile is good, accompanied by an adequate soil moisture regime and sufficient humus content, broad-leaved tree species like Dhak (Butea monosperma), Kaniar(Bauhinia purpurea), Pilu (Salvadora persica), etc., also thrive well. The native Dhak or Palas, commonly known as the ‘flame of the forest’, acts as an indicator of the clayey nature of the soil.

Express photo

4. Nine plant species that are planted are considered unsuitable for the Ridge ecosystem, including three exotics. Six are native species not naturally found in the Ridge, but considered only marginally adaptable under sustained irrigation and nutrient input.

5. Species lists from Central Ridge plantation drives between 2021 and 2025 include a limited set of Ridge-appropriate natives such as dhak (Butea monosperma), khair (Acacia senegal), Holoptelea integrifolia, and Cassia fistula. These species are naturally adapted to dry deciduous conditions and form part of the historical Aravalli-Ridge assemblage.

6. Exotic species include Sausage tree (Kigelia africana), Jacaranda (Jacaranda mimosifolia), and Jungle Jalebi (Pithecellobium dulce). Others such as Kadamba (Neolamarckia cadamba), Kachnar (Bauhinia variegata), and Bakain (Melia azedarach) are not characteristic of Ridge ecosystems and typically require higher moisture availability.

Leaves and flowers of Jungle Jalebi Pithecellobium dulce (Wikimedia commons)

7. A third category includes native Indian species that are not naturally part of the Ridge ecosystem, such as banyan (Ficus benghalensis), Peepal (Ficus religiosa), Semal (Bombax ceiba), and Bael (Aegle marmelos). While ecologically versatile, these species belong to different forest types.

8. Meanwhile, the Forest and Wildlife Department, in an official statement on June 22, maintained that a large-scale plantation programme in the Southern Ridge is underway wherein ecological restoration principles are being followed.

Initiatives to protect Ridge:

1. Serious initiatives to protect the Ridge started in the mid-1980s by a couple of Non-Governmental Organizations. To take a step forward in protection, the Delhi government appointed a committee under the chairmanship of Lovraj Kumar to recommend a pattern of management of the Delhi Ridge.

2. The Supreme Court further directed the Delhi Government to issue the process for the constitution of Reserved Forests of the area under the Ridge. The Supreme Court in the matter of  M.C. Mehta vs. Union of India and others cajoled the Delhi Government to constitute a Ridge Management Board for the protection of the Delhi Ridge in 1995.

3. The M.C. Mehta case directions led to the constitution of the Ridge Management Board on 6th October 1995 under the Chairmanship of the Chief Secretary, and consisted of 8 members, including the Chairman.

4. The Ridge Management Board, on its own volition, took a series of measures not only to carry out the directions of the Supreme Court, but also for the protection of the Ridge.

BEYOND THE NUGGET: What is the Morphological Ridge?

1. The Morphological Ridge is a geologically extended Ridge area. It is not officially notified as forest land but enjoys protection under several High Court and Supreme Court rulings over the past decade.

2. It possesses the same rocky outcrop and vegetative cover as the recognised Ridge area. The extent of the Morphological Ridge is based on a Delhi Forest Department map, itself based on the seismic zonation map of Delhi 2006, undertaken under the Geological Survey of India.

3. The region shares the same physical and ecological characteristics as the officially designated Ridge — rocky Aravalli outcrops, shallow soil layers, and dry thorn forest vegetation. This land is often recorded as “gair mumkin pahad” (uncultivable rocky hill) in revenue records.

4. The Morphological Ridge area primarily features tropical dry thorn forest characterised by scattered trees, thorny scrubs and drought-resistant plant species. The native species generally exhibit stunted growth. For instance, bistendu and the broad-leaved dhak, both native to Delhi, are common in such areas.

5. The vegetation varies as one moves from north to south within the Ridge and the Morphological Ridge, reflecting the changes in the soil texture. The southern Ridge is drier and more rugged, with thinner soils and exposed rocks, while the central and northern Ridges have slightly more water-retentive soil and denser vegetation.

Post Read Question

Consider the following statements:

1. The Lovraj Committee was constituted to suggest a management plan and pattern for the Delhi Ridge.

2. The Ridge Management Board was constituted on the Supreme Court’s directives in the M.C. Mehta vs. Union of India case.

3. Butea monosperma is commonly known as dhak or ‘flame of the forest.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

Answer Key

(d)

(Sources: Nearly 50% tree species planted recently at Central Ridge ‘unsuitable’ for terrain, At Delhi’s lone wildlife sanctuary, invasive tree covers 63.48% of landscape, Explained: The significance of the Delhi Morphological Ridge, Expert Explains | Why the Delhi government’s plans to restore the Ridge raise concerns, An Introduction to Delhi’s Ridge)

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