The assignment was to define the Aravallis, an ancient range of weathered hills rambling across four States, from the outskirts of Delhi to Gujarat. Despite three committees labouring over the task for over a year, armed with satellite imagery and expertise from multiple institutions, the Union government could not decide on uniform technical criteria to define the range.

It was only after the Supreme Court warned of initiating contempt proceedings against senior officials of the Environment Ministry that a new sub-committee was formed in August 2025, which then gave up trying to define the Aravallis and focussed instead on evolving a definition that would “balance” ecological consideration and the Centre’s 2019 National Mineral Policy that encourages mining of critical minerals for the “nation’s economic growth”, according to a 2,000-page affidavit by the Union Environment Ministry, submitted to the Supreme Court, which was perused by The Hindu.

Mining dangers

The definition of the Aravalli range has sparked an environmental and political firestorm over the last week, with charges that the government’s final definition only protects hills higher than 100 metres from mining. That leaves the remaining hills — which make up the vast majority of the 700 km range spanning from Haryana to Gujarat, with the bulk of it in Rajasthan — open to the dangers of mining and degradation.

Editorial | Debate on what is Aravalli reveals distrust of govt on ecological issues

Under fire from environmental activists and fighting a social media storm which alleged that vast tracts of the Aravalli ranges may be opened for mining, Environment Minister Bhupender Yadav has stressed that no new mining licenses would be awarded until a detailed Management Plan for Sustainable Mining (MPSM) covering the entire Aravalli range is prepared by the Indian Council of Forestry Research and Education, in line with the Supreme Court’s order on November 20, 2025. According to this directive, the plan must demarcate areas where mining must be absolutely prohibited, and identify zones where limited and highly regulated mining may be permitted.

Uniform definition

It was illegal mining, the hacking of the slopes of several hills, that triggered petitions in the past decades, and led to judicial intervention in the first place. To help decide on a uniform definition for the Aravalli hills, the Supreme Court constituted a Committee in 2024, comprising representatives from the Environment Ministry, the Forest Survey of India, State Forest Departments, the Geological Survey of India and the Central Empowered Committee of the Supreme Court. This Committee was tasked with creating a scientifically grounded, nationwide definition of the Aravallis. After constituting two sub-committees of its own, and facing a rap from the top court, the Committee finally submitted its findings in October 2025, after which the Supreme Court passed an order on November 20, 2025.

Perusal of the Committee’s documents showed that while the Forest Survey of India in 2010 had a criteria for defining the Aravalli hills in Rajasthan, based on the slope — and importantly, not on the height — the Committee was quite concerned that areas that were “not Aravalli” not be included.

“It is again reiterated that using only elevation and slope as criteria to demarcate the boundary of the Aravalli Hills and Ranges may lead to inclusion errors, as a significant part of Hilly area fall within the identified districts is non-Aravalli. In plain terms, not all areas of Aravalli have Hilly terrain and not all Hilly terrain in these 34 districts are necessarily Aravalli in terms of its Geological profile and extent,” it noted.

Slope and elevation

The first scientific attempt to define the Aravallis — till then only recognised as a geographical entity — and delineate it from other hilly terrain in Rajasthan, Gujarat, and Haryana came in 2010, when the Supreme Court asked the FSI, affiliated to the Environment Ministry, to delineate the ranges in Rajasthan. Mining had been banned in the State and there were several petitions by mining companies that the livelihoods of workers were in peril.

Under this definition, which was specific to Rajasthan, the Aravalli hills were those that had a slope greater than 3 degrees. The average elevation of the state was taken to be 115 m and to this, a uniform 100-metre wide buffer was added on the downhill side to account for slope stability. The flat areas, tabletops, depressions and valleys falling within this buffer were also included in the Hills. However there was no information presented on the number of hills included under such an exercise.

Until such an exercise, ‘core’ hills were defined as an elevated landform with a slope of 30 degrees or more, and a relative relief, or rise above the local ground level, above 300 m. To account for smaller hills that are often in the vicinity of core hills, those greater than a 17 degree slope and a 100 square km area around such hills, were deemed ‘hill areas’.

Technical sub-committee

A technical sub-committee of the main Committee, chaired by the Director General of the FSI, and including representatives from the Survey of India and the Geological Survey of India, in 2024 started on an exercise to define the ‘hills’ for all of the Aravallis beyond Rajasthan.

This exercise for the first time relied on standard resolution-maps prepared by the Survey of India. Even the FSI, the records show, concurred that the slope was not the sole determining criteria.

“The Survey of India (SoI) and the Forest Survey of India (FSI) were not in agreement with the approach of hard… based solely on slope and local relief,” a report of the Committee noted. “They emphasised that other local and regional morphometric parameters may also need to be considered. Since the nature of Hills varies across different terrains, it may not be practical to apply uniform criteria of slope and relief across the entire region. This observation was further substantiated during the detailed slope and relief-based analysis carried out by the Technical Sub-Committee.”

‘Take a policy decision’

Despite six meetings from May 2025 to August 2025, these experts could not agree on a uniform definition.

On August 12, 2025, the Supreme Court said that if “…recommendations were not submitted by the next date, the members of the Committee constituted in terms of our order dated 09th May, 2025, would be liable to be proceeded against for having committed Contempt of this Court…Basically, what is required to be done is to take a policy decision with regard to the definition of Aravali Hills and Ranges…we do not understand as to why a period of more than two months is required for arriving at a policy decision, which can be taken by the Secretary of the MoEF&CC by taking on board the representatives of all the State Governments…We are only interested in protecting the precious Aravali Hills and Ranges,” the order noted.

It was following this that the Committee started to focus on getting the views of States and getting a definition that would support sustainable mining. “…the Aravalli-Delhi system has been identified as having significant potential for critical minerals such as tin, graphite, molybdenum, niobium, nickel, lithium, and rare earth elements (REEs)…In this context, the Committee was of the considered opinion that while the ecological and environmental integrity of the Aravalli Hills and Ranges must remain the foremost priority, it is equally necessary to evolve a framework that enables systematic, scientific, and environmentally sustainable exploitation of critical, strategic, and atomic minerals located within the region. Such a balanced approach would ensure that the country’s strategic and developmental interests are not compromised,” the report noted.

It added: “The Committee after detailed deliberations felt that considering the wide variability of the elevation from Average Mean Sea Level (ASML) of Aravalli Hills and Ranges, the elevation with reference to local relief, as already being followed by Rajasthan and agreed to by other States, may be more appropriate and objective criteria for conservation and management of Aravalli Hills and Ranges.”