The Defence and Forest and Environment Ministries have given the go-ahead to the proposed 150-km alternate highway to NH 31A, exclusively for defence purposes in Sikkim and West Bengal.

The stretch from Damdim, Chalsa to Rhenock has been allotted to the National Highways Authority of India (NHAI) and the remaining 51 kilometre to the PWD department for expansion, Chief Engineer, Project Swastik, SS Powral, said.

The proposed route will cover Damdim, Chalsa, Khunia More, Jaldhaka and Tokday in West Bengal.

The Khunia More to Rhenock axis via Rachela a distance of about 75 km linked up with the 51 km stretch from Rhenock to Ranipool via Rorathang. The proposal was floated by BRO Project Swastik in 2010-11.

Defence sources said after the Ministry was informed that NHAI had expressed reservations over taking up the project in Darjeeling district in West Bengal, it was allocated to Project Swastik under Border Roads Oorganisation.

Meanwhile, the state government has been preparing the detailed project report on the upgradation of the road from Rhenock to Rorathang via Pakyong to Ranipool area which would be submitted soon.

At present, the condition of NH 31A was not the best for defence purposes, especially after the earthquake in 2011 and was very vulnerable, Powral added.