UPSC Mains 2019 GS Paper 3 Q17: model answer
Define the concept of carrying capacity of an ecosystem as relevant to an environment. Explain how understanding this concept is vital while planning for sustainable development of a region.
What the question wants
Define an ecosystem's carrying capacity and explain why it is vital for planning sustainable regional development.
How to structure it
Concept, then planning use.
- Definition
- Factors
- Why it matters in planning
- Indian cases
- How to apply
How to think it through
Carrying capacity: maximum population of a species (or human activity) an environment can sustain indefinitely without degrading it; determined by limiting resources (water, food, waste absorption). Human: depends on technology, consumption. Planning: hill towns (Shimla water crisis 2018), Joshimath subsidence 2023, tourism caps (Ladakh, Sikkim, Char Dham), Wayanad, Goa; SC asked for carrying capacity studies of Himalayan states (2024). Apply: carrying capacity studies before master plans, EIA cumulative, limits on construction, tourist permits, water budgets.
Model answer
In the summer of 2018, Shimla ran out of water, and residents told tourists to stay away. The town had been built for about 25,000 people in British times; it now held lakhs of residents and visitors. Shimla had crossed its carrying capacity.
The concept
- Carrying capacity is the largest population, or level of activity, that an environment can support indefinitely without being damaged.
- It is set by limiting factors: water, food, space, energy and the ability to absorb waste.
- For humans, it changes with technology and consumption: the same valley supports more people with efficient use, fewer with wasteful use.
Its parts
- Ecological: what nature can supply and absorb.
- Physical: land, slopes and infrastructure.
- Social: what local communities will tolerate.
Why it matters in planning
- Prevents overshoot, which leads to water shortages, pollution and disasters.
- Guides limits on construction, tourism and industry.
- Reveals cumulative impacts that single-project EIAs miss.
- Protects future generations, the heart of sustainable development.
Indian cases
- Joshimath (2023): land subsidence worsened by heavy construction on unstable slopes.
- Himalayan towns: in 2024 the Supreme Court asked for carrying capacity studies of hill states.
- Tourism caps: permits in Ladakh and Sikkim, and limits on visitors to some Himalayan shrines.
- Goa and Kerala's coasts face pressure from tourism and construction.
How to apply it
- Carrying capacity studies before master plans and tourism plans.
- Water budgets for towns and river basins.
- Zoning of fragile areas and building height limits.
- Regional, cumulative EIA instead of project-by-project clearance.
- Use of technology to raise capacity: rainwater harvesting, waste recycling, public transport.
- Local participation in setting limits.
Development that ignores carrying capacity borrows from nature, and nature always collects.
Draw: A curve rising to a ceiling (carrying capacity) and crashing after overshoot.
Keywords, cases and data to drop in
carrying capacity, limiting factors, overshoot, ecological footprint, Shimla 2018, Joshimath 2023, SC on Himalayan carrying capacity 2024, tourism caps, cumulative EIA, water budget.
Where most answers lose marks
- Giving only the textbook definition without the planning link.
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Question text as printed in the official UPSC Civil Services (Main) question paper. The model answer is original Battle IAS work; use it to learn structure, not to memorise.
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