NH Green Cover Index

Why in the News ?

The National Highways Authority of India has released the first National Highways Green Cover Index (NH-GCI), a technology-driven tool designed to assess the extent of vegetation and green cover along India’s national highways network.

The index has been developed in collaboration with the National Remote Sensing Centre under the Indian Space Research Organisation, using satellite-based remote sensing technologies to provide a scientific measurement of green cover along highway corridors.

The initiative marks an important step toward sustainable infrastructure development and environmental monitoring in India.

Background: Need for Green Infrastructure in Highway Development

India has rapidly expanded its road infrastructure in recent years to support economic growth, connectivity, and logistics efficiency.

The National Highways Authority of India manages a vast network of highways that form the backbone of the country’s transportation system.

However, large-scale highway construction can lead to:

• Loss of vegetation and biodiversity
• Increased carbon emissions
• Heat island effects
• Environmental degradation

To address these concerns, the government has emphasised green highways and large-scale roadside plantation programmes.

Monitoring the effectiveness of such plantation initiatives requires scientific and objective tools, which led to the development of the NH Green Cover Index.

What is the National Highways Green Cover Index (NH-GCI) ?

The National Highways Green Cover Index is a satellite-based index that quantitatively measures vegetation cover along national highway corridors.

It provides a scientific assessment of green cover within the Right of Way (RoW) of highways.

The index measures the percentage of land covered with vegetation along highways, including plantations along the left and right sides of roads and the central median wherever feasible.

By providing measurable data, the index allows policymakers to monitor environmental sustainability in highway development.

Role of Remote Sensing and Space Technology

The index has been developed with technical support from the National Remote Sensing Centre, a key research centre under the Indian Space Research Organisation.

Using high-resolution satellite sensors, scientists are able to detect vegetation through chlorophyll content present in plant leaves.

Satellite data allows authorities to monitor green cover across vast highway networks efficiently and accurately without extensive field surveys.

Methodology Used in the Index

The NH Green Cover Index uses advanced geospatial technologies to assess vegetation levels.

1. Satellite-Based Vegetation Detection

Vegetation is identified using chlorophyll signals captured by high-resolution satellite imagery.

These signals help determine whether land areas contain vegetation or barren surfaces.

2. Use of NDVI

The analysis relies on the Normalized Difference Vegetation Index (NDVI).

NDVI is a widely used remote sensing indicator that measures vegetation health by analysing how plants reflect light in different wavelengths.

Higher NDVI values generally indicate dense and healthy vegetation, while lower values indicate sparse or absent vegetation.

3. Segment-Wise Analysis

The assessment is conducted for every one-kilometre segment of the national highways network.

This granular analysis enables authorities to identify:

• Areas with strong green cover
• Areas with insufficient plantation
• Sections requiring intervention

4. Right of Way Assessment

The index measures vegetation within the Right of Way (RoW) of highways.

The Right of Way refers to the designated land corridor allocated for road infrastructure, including the carriageway, shoulders, medians, and roadside areas.

Significance of the NH Green Cover Index

1. Scientific Monitoring of Green Highways

The index provides a quantitative and objective method to measure green cover, replacing subjective field assessments.

2. Promoting Sustainable Infrastructure

It integrates environmental sustainability with infrastructure development, ensuring that highway expansion is balanced with ecological protection.

3. Improved Plantation Management

Authorities can identify areas with low vegetation cover and implement targeted plantation drives.

This will improve the effectiveness of green corridor initiatives.

4. Comparative Assessment and Ranking

The index enables comparison and ranking of highway stretches based on vegetation levels, encouraging better environmental performance.

5. Cost-Effective and Efficient Monitoring

Satellite-based monitoring provides a time-efficient and cost-effective method for assessing vegetation across thousands of kilometres of highways.

Broader Environmental Benefits

Enhancing green cover along highways offers several ecological benefits:

• Reduction in air pollution and dust
• Improved carbon sequestration
• Lower surface temperatures along road corridors
• Protection against soil erosion
• Creation of habitats for small wildlife species

These benefits contribute to climate resilience and environmental sustainability.

Challenges and Way Forward

1. Maintenance of Plantation

Plantation efforts often suffer from poor maintenance and survival rates.

Regular monitoring and irrigation systems must be ensured.

2. Integration with Climate Goals

The index should be integrated with India’s climate mitigation and afforestation targets.

3. Expanding Green Infrastructure

Future highway projects should include mandatory green planning, biodiversity corridors, and eco-sensitive designs.

4. Use of Advanced Geospatial Technologies

Continuous use of remote sensing, GIS mapping, and satellite monitoring will improve environmental governance in infrastructure development.

Significance

The NH Green Cover Index represents a major step toward data-driven environmental governance in infrastructure development.

By combining space technology with environmental monitoring, India is moving toward sustainable highway expansion that balances economic growth with ecological protection.

This initiative also highlights the growing role of satellite technology in environmental planning and policy implementation.