India's vital coastal artery, NH 66, faces a high-stakes transformation and ongoing safety struggles.

Countries & Cities · Published 3 October 2026 Swipe more like this →

In short: Spanning 1,640 kilometers along India's western coast, National Highway 66 is a critical economic lifeline connecting Mumbai to Kanyakumari. Once known as NH 17, this historic route is currently undergoing a massive, controversial expansion into a six-lane corridor, aiming to modernize connectivity despite significant engineering and environmental challenges.

National Highway 66 serves as the primary road link along India's western coast, traversing Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu. Historically, this route was the only major connection between coastal districts until the Konkan Railway opened in 1998. Today, it facilitates essential trade, linking major ports like JNPT, New Mangalore, and Kochi to the hinterland, while simultaneously driving tourism and regional development. Despite its importance, the highway has long been characterized by narrow, divider-less stretches, leading to high accident rates and congestion that often keeps average speeds lower than those on other major national highways.

The current overhaul, part of the Bharatmala Pariyojana, seeks to upgrade the road to a high-capacity, grade-separated highway. In Karnataka and Maharashtra, the project aims for a 60-metre right-of-way, while Kerala has adopted a 45-metre standard due to high population density and land costs. This expansion has faced intense scrutiny, including protests from local action groups and concerns over construction quality. Recent years have seen several infrastructure failures, such as a 2025 road collapse in Malappuram and a 2024 landslide in Shirur, which critics attribute to unscientific construction practices like vertical hill cutting.

Looking ahead, the Ministry of Road Transport & Highways is planning a new greenfield access-controlled expressway parallel to the existing highway in coastal Karnataka, mirroring the Mumbai-Pune model. As the project progresses, the government continues to balance the urgent need for modernized infrastructure with the complex realities of land acquisition, environmental sensitivity, and the safety of the millions who rely on this vital coastal corridor every day.

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