Last reviewed 4 Nov 2026 · 3 min read
1. Green buildings
A green building reduces negative impacts on the environment over its whole life — design, construction, operation, maintenance and demolition.
| Area | Measures |
|---|---|
| Site | Avoid sensitive land, protect topsoil and trees, reduce heat island |
| Energy | Orientation, shading, insulation, daylighting, efficient lighting and HVAC, rooftop solar |
| Water | Low-flow fixtures, rainwater harvesting, wastewater recycling, drip irrigation of landscapes |
| Materials | Local, recycled and low-embodied-energy materials — fly-ash bricks, AAC blocks, bamboo |
| Indoor quality | Ventilation, low-VOC paints, daylight |
| Waste | Construction-waste management, segregation during operation |
Rating systems
| System | By |
|---|---|
| GRIHA (Green Rating for Integrated Habitat Assessment) | TERI and the MNRE — India's national rating system |
| IGBC ratings | Indian Green Building Council (CII) |
| LEED | US Green Building Council — used internationally |
| ECBC (Energy Conservation Building Code) | Bureau of Energy Efficiency — minimum energy standards for commercial buildings; ECO-Niwas Samhita for homes |
2. Ecological footprint
DefinitionEcological footprint
The area of biologically productive land and water needed to produce the resources a person or population consumes and to absorb its wastes (mainly CO₂), measured in global hectares (gha). Developed by Mathis Wackernagel and William Rees (1990s).
- Biocapacity — the planet's (or a country's) capacity to supply these resources.
- If footprint > biocapacity → ecological deficit / overshoot.
- Humanity currently uses the resources of roughly 1.7 Earths a year (Global Footprint Network).
- Earth Overshoot Day — the date each year when humanity's demand exceeds what Earth can regenerate that year (falls around late July–early August in recent years).
- Carbon footprint — total greenhouse-gas emissions (as CO₂-equivalent) caused by a person, product or organisation; the largest part of the ecological footprint.
- Water footprint — total fresh water used, directly and indirectly (blue, green and grey water).