India has released its first National Highways Green Cover Index based on satellite monitoring of roadside vegetation across 30,000 km of highways. This ABC Live analysis examines how the system works, its environmental implications, and whether it truly measures ecological sustainability or simply detects vegetation pixels.
New Delhi (ABC Live): India’s highway expansion has entered a new environmental phase. Recently, on 9 March 2026, the Government of India released the National Highways Green Cover Index (NH-GCI) Annual Report 2025–26. As a result, India now has its first nationwide satellite-based assessment of vegetation along highways.
The National Remote Sensing Centre (NRSC) of ISRO prepared the report in collaboration with the National Highways Authority of India (NHAI).
👉 Official announcement
Press Information Bureau
https://www.pib.gov.in/PressReleasePage.aspx?PRID=2237080
In simple terms, the initiative uses satellite imagery and GIS mapping to measure vegetation along highway corridors. More importantly, the system evaluates vegetation density every one kilometre along the highway network. Consequently, policymakers can compare vegetation levels across different corridors.
At present, the first monitoring cycle covers around 30,000 kilometres of highways across 24 states. Importantly, the analysis relies on satellite observations collected between July and December 2024.
However, at the same time, India continues to expand one of the largest highway networks in the world under programs such as Bharatmala Pariyojana.
On the one hand, new highways improve logistics, trade, and mobility. On the other hand, they can also create environmental risks such as:
- forest loss
- habitat fragmentation
- soil erosion
- ecosystem disruption
Therefore, the key question is no longer whether highways should be greener.
Instead, the more important question is this:
Does satellite-detected green cover actually reflect ecological restoration, or does it simply detect vegetation pixels?
Moreover, the launch of the Green Cover Index reflects a broader shift toward technology-driven environmental monitoring in India. Nevertheless, the initiative also raises questions about how policymakers should measure infrastructure sustainability.
Environmental Governance Dashboard
To begin with, the NH-GCI project represents a major shift in environmental monitoring. Previously, highway agencies relied mainly on field inspections to evaluate roadside plantations. Now, however, satellite data allows authorities to observe vegetation across the entire national highway network.
| Governance Dimension | Current Status | Assessment |
|---|---|---|
| Policy framework | Green Highways Policy (2015) | Strong |
| Monitoring technology | Satellite NDVI monitoring | Advanced |
| Ground verification | Limited field surveys | Moderate |
| Transparency | Restricted technical report | Weak |
| Biodiversity indicators | Not included | Weak |
| Climate integration | Still developing | Moderate |
Consequently, the dashboard shows that although monitoring technology has improved significantly, environmental governance still depends on stronger ecological indicators.
For example, the system does not yet track:
- tree survival rates
- biodiversity recovery
- wildlife corridor health
- carbon storage
As a result, the index measures vegetation presence rather than ecosystem health.
At the same time, however, technology alone cannot guarantee ecological sustainability.
How the Monitoring System Works
In practice, however, the NH-GCI system divides highways into one-kilometre segments.
Then, analysts use satellite imagery to estimate vegetation density using the Normalised Difference Vegetation Index (NDVI).
Monitoring workflow
First, the system collects satellite images.
Next, engineers geometrically correct the images.
After that, the system calculates NDVI values.
Then, the software classifies vegetation pixels.
Finally, the system generates the Green Cover Index.
The system mainly relies on Resourcesat-2 and Resourcesat-2A imagery, which provide spatial resolution of about five metres.
In addition, analysts use Cartosat-2S imagery with finer resolution to verify the results.
Furthermore, the kilometre-level segmentation allows authorities to identify areas where plantation performance improves or declines over time.
As a result, policymakers can monitor vegetation changes along highways more systematically.
Remote Sensing Risk Matrix
Although satellite monitoring offers powerful capabilities, several technical limitations remain.
| Risk | Description | Impact |
|---|---|---|
| Mixed pixels | Soil and vegetation share one pixel | Moderate |
| Narrow plantations | Trees smaller than pixel width | High |
| NDVI confusion | Grass or crops detected as vegetation | High |
| Seasonal variation | Monsoon greening spikes | Medium |
| Cloud cover gaps | Missing imagery during the monsoon | Medium |
| Location errors | ±5 m positional shift | Low |
For example, roadside trees often occupy only a small part of a satellite pixel.
Consequently, the system may overestimate vegetation density.
In other words, the index measures green pixels rather than ecological quality.
Nevertheless, satellite monitoring still offers an important advantage because it enables nationwide environmental observation.
Otherwise, authorities would need thousands of field inspections.
Climate Impact Analysis of Highway Plantations
Even so, roadside plantations can still produce important environmental benefits.
| Climate Benefit | Mechanism |
|---|---|
| Carbon capture | Trees absorb CO₂ |
| Dust control | Leaves trap pollutants |
| Heat reduction | Tree shade lowers road temperature |
| Soil stability | Roots prevent erosion |
| Wildlife support | Vegetation forms ecological corridors |
If policymakers manage these plantations properly, highway vegetation could contribute to India’s climate strategy.
However, the current NH-GCI system does not yet estimate carbon storage or biomass growth.
ABC Live previously examined the need for stronger climate data systems in its analysis:
👉 India’s Strategic Climate Knowledge Mission
https://abclive.in/2025/07/31/indias-strategic-climate-knowledge-mission/
Similarly, the long-term climate value of highway plantations will depend not only on vegetation density but also on tree survival and ecosystem stability.
Consequently, policymakers must integrate satellite monitoring with ecological data.
Global Comparison: How Countries Green Highways
Many countries adopt ecosystem-focused strategies for highway greening.
| Country | Strategy | Key Feature |
|---|---|---|
| Netherlands | Wildlife corridors | Animal bridges |
| United States | Habitat restoration | Native vegetation |
| Japan | Noise barrier forests | Urban tree belts |
| China | Ecological expressways | Continuous green corridors |
| India | Plantation monitoring | Satellite vegetation index |
Therefore, international experience shows that successful highway greening programs combine plantation initiatives with broader ecosystem restoration.
Final Assessment
Ultimately, the National Highways Green Cover Index represents an important step toward data-driven environmental monitoring.
However, satellite monitoring alone cannot guarantee ecological sustainability.
Ultimately, the effectiveness of the system will depend on how policymakers interpret and use the data.
In other words, satellite monitoring must work alongside transparent governance, ecological science, and long-term plantation management.
Therefore, the NH-GCI system should be seen as the beginning of a monitoring framework rather than the final solution.
