NHAI Releases Document on ‘Wildlife Mitigation Measures & Structures’ Highlighting Strengthened Wildlife Conservation Measures Along National Highways

1. At a Glance

• What it is: a reference document from the National Highways Authority of India (NHAI) on how wildlife protection is built into the planning, design and construction of National Highways (NH) [1].
• Headline numbers: about ₹19,700 crore spent on wildlife mitigation and environmental safeguards in the last five years, and more than 2,150 wildlife mitigation structures built and/or proposed [1].
• Problems it targets: habitat fragmentation, barrier effects and wildlife–vehicle collisions, while keeping traffic moving safely [1].
• Why it matters for UPSC: it sits where GS-III Infrastructure meets Environment/Biodiversity. It is a ready example for "development vs. conservation" answers and Prelims questions on terms such as Animal Under Pass (AUP), canopy crossing and guide fencing.

2. Why in the News

• Released to mark National Wildlife Week, 2–8 October 2026. PIB release dated 8 October 2026 [1].
• Released by Union Minister for Road Transport & Highways Nitin Gadkari at the Chintan Shivir, Ekta Nagar, Gujarat [1].
• The full document is hosted on the NHAI website (nhai.gov.in, "NHAI-Wildlife_Mitigation_Measures_and_Structures.pdf") [1].

3. Background & Evolution

• Guiding framework: the National Tiger Conservation Authority (NTCA) and the Wildlife Institute of India (WII) published "Eco-Friendly Measures to Mitigate Impacts of Linear Infrastructure on Wildlife" [5]. Publication year not confirmed in the sources retrieved.
• NBWL link: MoRTH says it takes the wildlife protection steps prescribed by the National Board for Wildlife (NBWL) [4].
• Milestones (order as reported by PIB, exact dates not verified):
• Table-Top Red Marking: India's first on a highway, on an 11.96 km forest/ghat stretch with 25 dedicated animal underpasses and chain-link fencing [3].
• NHAI–WII study "Landscapes Reconnected": first evidence of wildlife using the underpasses on the Delhi–Dehradun Economic Corridor (Ganeshpur–Asharodi) [2].
• Oct 2026: this consolidated document [1].

4. Core Static Facts

Item	Fact
Releasing body	NHAI, under the Ministry of Road Transport & Highways (MoRTH) [1]
Total investment (last 5 yrs)	~₹19,700 crore [1]
Number of structures	More than 2,150, built and/or proposed [1]
Structural measures	Underpasses, overpasses, culverts, canopy crossings, bridge-cum-AUPs (major and minor), culverts adapted for animal movement, specialised structures [1]
Non-structural measures	Signage, fencing, speed regulation, noise barriers, reptile crossings, rainwater harvesting [1]
Guide fencing + noise barriers	On more than 300 km of NH alignments [1]
Monitoring	Camera traps; collision hotspots identified and given speed boards and signs [1]
How mitigation is planned	By ecological sensitivity of the corridor, wildlife movement patterns, and technical feasibility [1]

Structural spending breakdown [1]:

Structure	₹ crore
Viaducts	8,300 (largest)
Animal underpasses	4,600
Tunnels	2,800
Major bridges	2,500
Animal overpasses	650
Minor bridges	500

These six items add up to about ₹19,350 crore (my sum of [1] figures).

Underpass design rule (NTCA/WII): height at least equal to width, with openings that give an unobstructed view of the habitat. Existing culverts and drainage points can be retrofitted as animal passages [5].

5. Multi-Dimensional Analysis

Environmental

• Keeps habitats connected across highway corridors and reduces fragmentation and barrier effects [1].
• The NTCA/WII guidance also covers construction practice: no night work inside forests, labour camps at least 1 km from forest, and no high-mast lights or loud noise within 1 km of a protected area boundary [5].

Scientific / Technological

• Evidence from monitoring: on the Delhi–Dehradun corridor, a 40-day study used 150 camera traps and 29 AudioMoth acoustic recorders. It recorded 40,444 images of 18 wild species and 60 elephant crossings [2].
• Low-cost engineering fix: a 5 mm hot-applied thermoplastic red layer that is slightly raised, so drivers feel and hear it and slow down without sudden braking [3].

Economic

• Viaducts take the largest share of spending (₹8,300 crore of the structural total), which shows that elevated alignments are expensive to build [1].
• Mitigation is now a routine part of project cost. It is planned at different stages of NH development rather than added later [1].

Governance / Administrative

• Calls for collaboration between conservation bodies and highway agencies, alongside statutory environmental compliance [1].
• Periodic evaluation through camera trapping makes the measures checkable after construction [1].
• MoRTH aligns its measures with NBWL prescriptions [4].

Social / Safety

• Collision-hotspot measures protect highway users as well as wildlife [1].
• Fencing guides animals toward the underpasses and keeps them off the carriageway [3].

6. Recent Developments (last 12–18 months)

• Oct 2026: NHAI releases the 'Wildlife Mitigation Measures & Structures' document [1].
• 2025–26 (exact date not verified): NHAI–WII report "Landscapes Reconnected" on the Delhi–Dehradun Economic Corridor. The Ganeshpur–Asharodi stretch has about 10.97 km of animal underpass along roughly 20 km [2].
• 2025–26 (exact date not verified): India's first Table-Top Red Marking on a highway, with 25 AUPs over 11.96 km [3].

7. Prelims Hooks

• The document was released by NHAI (under MoRTH), not MoEFCC [1].
• It was released at the Chintan Shivir, Ekta Nagar (Gujarat) [1].
• It marked National Wildlife Week (2–8 October) [1].
• Investment in wildlife mitigation over five years: ~₹19,700 crore [1].
• Wildlife mitigation structures built and/or proposed: >2,150 [1].
• Viaducts got the largest structural spend (₹8,300 crore). Animal overpasses got only ₹650 crore [1].
• Guide fencing and noise barriers cover >300 km of NH [1].
• Canopy crossings are a structural measure, used mainly by tree-dwelling animals such as primates [1].
• Reptile crossings are listed by NHAI as a non-structural measure [1].
• "Eco-Friendly Measures to Mitigate Impacts of Linear Infrastructure on Wildlife" was published by NTCA + WII [5].
• NTCA/WII rule: underpass height ≥ width [5].
• "Landscapes Reconnected" is an NHAI–WII study of the Delhi–Dehradun Economic Corridor [2].
• That study recorded 18 species and 60 elephant crossings using underpasses [2].
• India's first Table-Top Red Marking on a highway: 11.96 km, 25 AUPs, 5 mm thermoplastic layer [3].

8. Only About a Quarter of the ₹19,700 Crore Is for Animal-Only Crossings

• Most of the money goes on structures a highway in hilly or river country often needs anyway
• Viaducts (₹8,300 crore), tunnels (₹2,800 crore), major bridges (₹2,500 crore) and minor bridges (₹500 crore) make up most of the structural spending [1].
• A viaduct (a long raised road on pillars) or a tunnel lets animals pass. But engineers also build them to cross valleys, hills and rivers. So not every rupee here was spent only because of wildlife.

• Structures built only for animals, underpasses (₹4,600 crore) and overpasses (₹650 crore), add up to about ₹5,250 crore. That is roughly a quarter of the headline figure (my sum of [1] figures).

• 'Built and/or proposed' mixes finished work with plans

• The figure of more than 2,150 structures counts both [1].

• The release does not say how many are finished and working. So the number cannot yet be read as protection already on the ground.

• The document counts money spent, not animals saved

• The headline numbers measure inputs: rupees and structures [1].
• It gives no national figure for roadkill (animals killed by vehicles) before and after the structures were built. Without that, nobody can judge whether ₹19,700 crore was spent in the right places.

9. Built for Elephants, While Snakes and Birds Die Most

• Most animals killed on roads are small, but the main structures are designed for big mammals
• A WII–NTCA survey counted 1,176 roadkills on NH 715 (earlier NH 37), which passes Kaziranga Tiger Reserve, during January–December 2019 [7].
• Reptiles were 585 of these, about half. Birds were 411 and small mammals 129. Large mammals were only 41 (3.48%) [7].

• The NTCA/WII underpass rule (height at least equal to width) is written for large animals [5]. A snake or a frog needs a small, low passage close to the ground.

• Reptile crossings are filed under 'non-structural'

• NHAI groups reptile crossings with signboards and speed limits, not with engineered structures [1].

• That puts the animals killed most often in the category that gets less engineering money.

• Threatened species are among the dead, not just common ones

• On NH 715 the dead included 35 hog deer, plus Burmese pythons, the slow loris, the capped langur and the Indian softshell turtle [7].
• So small-animal deaths are a conservation problem, not just a nuisance.

10. Why Camera-Trap Results Can Make a Road Look Safer Than It Is

• Showing that animals use an underpass does not show that fewer animals die
• The Delhi–Dehradun study counted animals passing through the structures, for example 60 elephant crossings [2].

• That proves the structures are used. It does not count deaths on stretches outside the structures, or deaths of animals too small for the cameras to record.

• Dead bodies disappear fast, so roadkill counts come out too low

• On NH 715, large mammal carcasses (hog deer, sambar, langur) stayed on the road for less than 12 hours [7].
• People and forest staff removed them, sometimes for illegal consumption [7]. Pythons lasted at most 3 days and turtles about 48 hours [7].

• A survey done only now and then misses many deaths. The real toll is higher than what gets recorded.

• A 40-day study can miss the dangerous season

• The Delhi–Dehradun monitoring ran for 40 days [2].
• At Kaziranga, roadkill changed sharply from month to month. Hog deer and sambar deaths peaked in July–August, when animals cross NH 715 to escape monsoon floods and reach the Karbi Anglong hills [7].

• A short study can fall in a quiet month and give a falsely good picture.

• Animals can avoid the road even when they are not hit

• This is the barrier effect: the road blocks movement even with no collision.
• At Kaziranga, hog deer groups got bigger the farther they were from the road. Signs of animals fell where vehicle noise was present [7].
• Ungulates (hoofed animals such as deer) avoid noisy strips, so their habitat shrinks even when roadkill is zero. Underpass counts do not capture this loss.

11. Do Animal Crossings Make It Easier to Push Roads Through Forests?

• The strongest objection
• Once a highway can promise underpasses and viaducts, cutting through a tiger reserve or corridor (a strip of forest linking two habitats) looks acceptable. Mitigation then becomes a reason to approve the route instead of a last resort.

• The disturbance does not stop at the structure. Noise and traffic keep animals away from the roadside even where they can cross safely [7]. A raised road still brings that disturbance into the forest.

• What the objection gets right

• Mitigation reduces harm. It does not undo it. The NH 715 study calls the highway's impact on the Kaziranga–Karbi Anglong corridor 'devastating', even with signboards and 'animal corridor' speed zones in place [7].

• So NHAI's spending figures should never be presented as proof that a forest route is harmless.

• Where the objection is weaker

• Many highways, like NH 715, already run through these landscapes. Animals have no other route, for example during Kaziranga's floods [7].

• For roads like these, removing the road is not on the table. The real choice is between mitigation and no protection at all. Here structures such as viaducts are the best option available.

• The honest answer: first avoid the forest. Where that is impossible, reduce the damage. Where an existing road cannot be moved, add crossings. The NTCA/WII guidance [5] and NBWL prescriptions [4] should be used in this order, not to skip the first step.

12. What NHAI and WII Should Measure Next

• NHAI and WII should run year-long roadkill surveys before and after building
• The NH 715 study is the model: a full 12-month count, all animal groups, and heatmaps (maps showing where collisions cluster) to find hotspots [7].

• Doing this before and after a structure is built would show deaths avoided, not just crossings recorded.

• MoRTH should write small-animal passages into design standards

• About half the roadkill on NH 715 was reptiles [7]. Yet reptile crossings sit among non-structural measures [1].

• Small, low passages near wetlands and water bodies should be treated as engineered structures with their own budget line.

• Plan for the season, not just the location

• At Kaziranga, deaths peak when floods push animals across the road in July–August [7].

• Seasonal speed limits or traffic control on flood-escape stretches would target the deadliest weeks.

• NHAI should report completed structures separately from proposed ones

• Splitting the 2,150 figure into 'working' and 'planned', with the cost of each, would make the ₹19,700 crore claim checkable [1].

13. Anchors for Answers

• Data: 1,176 roadkills recorded on NH 715 (Kaziranga) in 2019. Reptiles were about half; large mammals only 3.48% [7]
• Data: Animal-only crossings (underpasses ₹4,600 crore + overpasses ₹650 crore) are about ₹5,250 crore of the ₹19,700 crore headline [1]
• Data: Large mammal carcasses lasted under 12 hours on NH 715, so roadkill is under-counted [7]
• Report/Committee: WII–NTCA, 'Assessment of Impacts of National Highway 715 (Earlier NH 37) on Wildlife Passing through Kaziranga Tiger Reserve', TR No. 2020/11 (2020) [7]; NTCA/WII 'Eco-Friendly Measures to Mitigate Impacts of Linear Infrastructure on Wildlife' [5]; NHAI–WII 'Landscapes Reconnected' [2]

14. Mains Relevance

• GS-III: Infrastructure (roads); Conservation, environmental pollution and degradation; Environmental Impact Assessment.
• GS-II: Government policies and inter-agency coordination (MoRTH–NBWL–WII).
• Possible question stems: 1. "Linear infrastructure is the biggest driver of habitat fragmentation in India." Examine how wildlife mitigation structures help reconcile highway expansion with biodiversity conservation. 2. Discuss the role of evidence-based monitoring (camera traps, acoustic sensors) in judging whether eco-friendly infrastructure works. Illustrate with Indian examples. 3. Should mitigation structures replace avoiding protected areas when aligning highways? Critically analyse.

15. Related Topics to Study Next

• NTCA/WII guidelines on linear infrastructure: the base technical framework for these measures [5].
• National Board for Wildlife (NBWL) and its Standing Committee: clears projects in protected areas and prescribes mitigation [4].
• Tiger and elephant corridors (NTCA corridor management): the landscapes that crossings are meant to reconnect [5].
• Delhi–Dehradun Economic Corridor: flagship case study of elevated wildlife corridors [2].
• NHAI "Bee Corridors" initiative: another NHAI biodiversity project along highways [6].
• Environmental Impact Assessment (EIA) and Forest Conservation Act clearances: the statutory compliance layer [1].
• Railway-line elephant deaths and Project Elephant: parallel problem with linear infrastructure [5].

16. NCERT Concepts to Revise

• National Highways Authority of India (Geography): NHAI is the body that released the document and builds these wildlife crossings on highways.
• National Tiger Conservation Authority (Geography): NTCA and WII wrote the guidelines on linear infrastructure and underpass design that NHAI follows.
• Environmental impact assessment (Economy): EIA is the statutory clearance process that prescribes mitigation measures before highways cut through forests.
• Biodiversity conservation (Geography): The note's central tension is balancing highway development with protecting habitats and species.
• Project Elephant (Geography): Elephant corridors and crossings are a key case, and the note links railway elephant deaths to the same problem.
• Threatened species (Geography): Roadkill on NH 715 included threatened species like slow loris and Indian softshell turtle.

17. Common Errors / Trap Areas

• Wrong ministry: the document is from NHAI/MoRTH, not MoEFCC. The guidelines it builds on came from NTCA/WII [1][5].
• Mixing up the numbers: ₹19,700 crore is total investment, while 2,150 is the number of structures. Also, "built and/or proposed" does not mean all are completed [1].
• Biggest spend: it is viaducts (₹8,300 crore), not animal underpasses (₹4,600 crore) [1].
• Classification: NHAI puts noise barriers and reptile crossings under non-structural interventions, not structural ones [1].
• National Wildlife Week (2–8 Oct) vs. World Wildlife Day (3 March): the second date comes from general knowledge, not the retrieved sources.