CHENNAI: A proposed highway corridor cutting through the Sengottai (Aryankavu) Gap in the southern Western Ghats, involving long tunnels and large-scale rock excavation, is drawing concern from conservationists who warn that the fragile mountain pass is both a critical wildlife corridor and a landslide-prone landscape. The National Highways Authority of India (NHAI) has submitted a proposal seeking wildlife clearance from the National Board for Wildlife for the project.
The corridor is part of the Puliyarai–Aryankavu–Kadampattukonam economic corridor under the Bharatmala programme and is intended to improve freight connectivity between Tamil Nadu and the Kerala coast. The project will link NH-744 (Kollam–Madurai) with NH-66 (Mumbai–Kanniyakumari), forming a key east–west freight route across the Western Ghats.
While the entire corridor is planned over 61.7 km, the most ecologically sensitive section is Package-1 — a 23-km stretch between Puliyarai in Tenkasi district and Edamon in Kollam district. Of this, around 4 km lies in Tamil Nadu and 18.96 km falls in Kerala.
The proposed alignment runs through the Sengottai (Aryankavu) Gap, a rare break in the Western Ghats mountain chain that forms a natural passage between the two states. The region lies within the Agasthyamalai landscape, where forests connect several protected areas including Kalakad–Mundanthurai Tiger Reserve and Shendurney Wildlife Sanctuary, which in turn link to Periyar Tiger Reserve, Peppara and Neyyar wildlife sanctuaries.
The corridor between Periyar and Shendurney is considered crucial for the long-term movement of tigers and other wildlife. The landscape is estimated to support around 36–40 tigers across more than 2,100 sq km of habitat.
However, the Aryankavu pass already contains transport barriers including NH-744 and the Kollam–Sengottai railway line. Project maps accessed by TNIE show the alignment passing through Puliyarai Reserved Forest in Tamil Nadu and Ariankavu and Yerur Reserved Forests in Kerala, close to eco-sensitive zones.
To negotiate the steep terrain, the project proposes four tunnel roads for the two carriageways of the four-lane highway. The tunnels range from about 420 metres to over 3.7 km in length and around 11 metres in height.