The NH-GCI is derived from chlorophyll detection by high-resolution satellite sensors and is reported as a per cent value representing the proportion of land within the Right of Way covered by green vegetation at a granularity of one kilometre. The assessment accounts for vegetation on both the left and right sides of highways and applies uniform technological criteria to ensure comparability. The methodology enables technology-driven macro-level estimation across long corridors.
In the first assessment cycle, approximately 30,000 km of national highways across 24 states were analysed for the period July to December 2024, and subsequent annual cycles will be used to monitor year-on-year change. The work was undertaken under a three-year memorandum of understanding signed in January 2024 between NHAI and NRSC and is intended to provide a reliable, time-efficient and cost-effective mechanism for estimating green cover. The findings are designed to support comparison, ranking and targeted interventions for improved plantation management along highway corridors.
The NH-GCI initiative reflects NHAI's commitment to environmental sustainability and to advancing the green transformation of the national highway network. The report is expected to inform policy decisions and operational planning and to guide stakeholders in prioritising plantation and maintenance activities. A copy of the report is available on the NHAI website and stakeholders are encouraged to consult the published document for technical details and further guidance.