Delhi’s Only Wildlife Sanctuary Choked by Invasive Tree: WII Plan for Asola Bhatti

CURRENT AFFAIRS | MAY 14, 2026

Delhi’s only protected forest is being silently swallowed by a foreign tree. A newly released 10-year management plan by the Wildlife Institute of India (WII) for the Asola Bhatti Wildlife Sanctuary reveals that the invasive Mexican mesquite — Prosopis Juliflora, locally called vilayati keekar — now blankets 63.48% (~12 sq km) of the sanctuary’s 18.41 sq km area. Native vegetation is gasping at just 18.83%, while rocky outcrops cover 14.07%, the invasive shrub Lantana Camara 1.55%, and water bodies barely 0.76%.

For a sanctuary that is the last green lung of Delhi’s Southern Aravalli Ridge, these numbers describe a quiet ecological collapse — and a constitutional and statutory test of how India balances development, protected-area governance, and the right to a healthy environment under Article 21.

The WII plan calls for phased mechanical removal of Prosopis combined with assisted regeneration of native Aravalli species like Anogeissus pendula (dhok) and Boswellia serrata (salai). But removal is fraught — the deep-rooted shrub regenerates from broken stumps, and any large-scale uprooting can destabilise the thin Aravalli soil. The plan also flags an unrelated but compounding pressure: around 20,000 rhesus macaques have been dumped into the sanctuary from across Delhi over the years, now exceeding its carrying capacity and driving them into nearby villages.

The Prosopis story is itself a colonial inheritance. The British introduced it in the 1930s to green Delhi’s bare ridge and provide fuelwood. It grew faster than anyone planned for, displaced native flora, depleted groundwater, and reduced biodiversity by emitting allelopathic chemicals that prevent other plants from germinating in the same soil. The economic loss across India is estimated in thousands of crores. Yet, it cannot be uprooted overnight — local livelihoods depend on its fuelwood and charcoal.

For aspirants, the larger frame matters: this is a protected-area-governance story, an invasive-alien-species story, and a federal-environmental-law story rolled into one — and almost every one of those threads has been litigated before the Supreme Court, the National Green Tribunal, and the Delhi High Court.