The Dr. Syama Prasad Mookerjee Tunnel, also known as the Chenani-Nashri Tunnel, is currently the longest road tunnel in India, measuring 9.28 km in length. Although the Zojila Tunnel is under construction and will eventually become the longest, it is not yet completed. Therefore, the Dr. Syama Prasad Mookerjee Tunnel remains the longest as of now.