India builds Wildlife Overpasses on Delhi-Mumbai Expressway

The 1,350-kilometre-long (840 mi) and eight-lane-wide Delhi–Mumbai Expressway is one of the most important projects undertaken by the National Highways Authority of India (NHAI) under the Ministry of Road Transport and Highways.

To be completed by 2027 for $13.1 billion, making it one of the most costly infrastructure projects in the country. Passing through 6 different states, this highway will create an important commercial and trade link between India’s national capital, New Delhi and its financial capital, Mumbai.

Considering the long distance, the expressway passes through major ecological zones and wildlife reserves, including the Aravalli mountains, Sariska Tiger Reserve, Mukundara Hills National Park, Ranthambore National Park and Ramgarh Vishdhari Wildlife Sanctuary.

These forest zones are home not just to India’s national animal, the tiger, but to a wide variety of wild animals, including leopards, sloth bears, hyenas, desert cats, caracals, jackals, and striped hyenas, among many others.

These wild animals often move out of their habitats and wildlife reserves in search of food or water. Additionally, climate change and human actions alter their ecosystems, pushing animals to migrate in search of more favourable conditions.

Sometimes, population growth of a particular species within protected areas causes animals to move beyond reserve boundaries. This is especially applicable to tigers in the region as they require large territories to find enough prey and establish their range. They are forced to move across non-forest areas to find food, mates, or new territory.

Ranthambore Tiger Reserve, one of the wildlife regions impacted by the Delhi–Mumbai Expressway, has an estimated population of over 80 tigers. Often, due to overcrowding, tigers migrate to other sanctuaries and reserves. In one instance, T-38, a tiger from Ranthambore National Park, strayed to Kuno Wildlife in Madhya Pradesh at the age of 4, only to return a decade later.

When this happens, tigers and other animals often pass through human habitats, villages and roads, leaving them vulnerable to human-wildlife conflict. Infrastructure like roads, railways, and settlements breaks up animal habitats into disconnected patches.

In addition to conflict, animals also face the danger of road and railway accidents, especially when they try to cross highways or tracks that cut through forests.

Unlike forest paths, roads are unfamiliar and disorienting to large animals like tigers and leopards. Bright lights, noise, and traffic confuse them, making them more likely to freeze or panic while crossing, which increases accident risk. These crossings can result in fatal injuries or death for the animals and even pose a threat to human life.

To mitigate this situation, NHAI is building wildlife overpasses on the stretches identified as the known wildlife corridors between the forest and tiger reserves.

The corridor, passing through Ranthambore Tiger Reserve’s buffer zone, includes five 500-metre-long natural-looking wildlife crossings and a 1.2-km underpass, all built to preserve natural contours.

One of these wildlife crossings will be an underground road tunnel below the Mukundara Hills National Park, which will be the country’s first 8-lane tunnel. Additionally, to avoid disturbance to the tiger reserve, both ends of the tunnel are placed about 500m away from the boundary of the protected area of Mukundra Hills Tiger Reserve.

Developed by the NHAI in consultation with wildlife experts, the animal crossings on the Delhi–Mumbai Expressway will provide a safe passage for tigers, leopards, and other wildlife.

Elephants on Roads

Apart from the native trees and plants, the wildlife overpasses over the expressway will have 8-meter-tall noise barrier walls on either side. The uncovered stretch of expressway will have 6-foot-tall walls on both sides to prevent animals and pedestrians from entering.

Plans are to plant 35,000 trees and incorporate features like rainwater harvesting, reflecting a holistic approach to sustainable development.

In countries like the Netherlands, Canada, and the United States, wildlife overpasses have proven effective in minimising roadkill and preserving ecological balance.

India’s initiative aims to replicate this successful model, reduce human-animal conflict, offer a blueprint for balancing economic progress with environmental preservation, and signal a shift in national infrastructure planning.