Katraj is suburb of Pune in Maharashtra state of India and within the jurisdiction of Pune Municipal Corporation. The adjacent hill is called Katraj Ghat (mountain pass). Katraj Snake Park is located at Katraj. It lies on the Mumbai - Chennai National Highway. It is one of the southernmost areas of the city.
In olden times, the road from Pune to Satara went over the top of the hill. A tunnel (the old tunnel) was constructed when two-lane national highway, NH4, was constructed in 1960s. A new tunnel was bored through the hill for widening the highway to four lanes in 2007.
The New Katraj Tunnel is located on the NH 4, Pune, India. It is a three-lane tunnel. The tunnel is 1,338 metre long . This tunnel replaced the Old Katraj Tunnel. The road includes construction of an entirely new tunnel to bypass the older routes and one of the tallest viaduct in India (510 meters). The construction was undertaken by ShaktiKumar Sancheti.