Atal Tunnel

Atal Tunnel (also known as Rohtang Tunnel)[1] is a highway tunnel built under the Rohtang Pass in the eastern Pir Panjal range of the Himalayas on the Leh-Manali Highway in Himachal Pradesh, India.[2][3] At a length of 9.02 km, it is the longest tunnel above 10,000 feet (3,048 m) in the world and is named after former Prime Minister of India, Atal Bihari Vajpayee.[4]

Atal Tunnel
PM Modi in Atal Tunnel 2020.jpg
LocationRohtang, Himachal Pradesh, India
Coordinates32°24′05″N 77°08′54″E / 32.401270°N 77.148335°E / 32.401270; 77.148335
RouteLeh–Manali Highway
Work begun28 June 2010
Opened3 October 2020
OperatorBorder Roads Organisation
TrafficMotor vehicles
Length9.02 kilometres (5.60 mi)
No. of lanesTwo (one in each direction)
Operating speed40–80 km/h (25–50 mph)
Width10 metres (33 ft)
PM Narendra Modi at the entrance to the Atal Tunnel

The tunnel reduces the travel time and overall distance between Manali and Keylong on the way to Leh. The route, which previously went through Gramphu, was 116 km (72.1 mi) long and took 5 to 6 hours in good conditions. The traveller now reaches the South Portal of the tunnel from Manali, a distance of 24.4 km (15.2 mi) in about 50 minutes, goes through the 9.02 km (5.6 mi) long tunnel in about 15 minutes, and reaches Keylong which is 37 km (23.0 mi) away in about 60 minutes. The new route via the tunnel brings down the total distance travelled to 71 km (44.1 mi) which can be covered in about 2 hours and 5 minutes, a reduction of around 3 to 4 hours when compared to the earlier route. Moreover, the tunnel bypasses most of the sites that were prone to road blockades, avalanches, and traffic snarls.[5][6]

The tunnel is at an elevation of 3,100 metres (10,171 ft) whereas the Rohtang Pass is at an elevation of 3,978 metres (13,051 ft). It was inaugurated by Prime Minister Narendra Modi on 3 October 2020. The cost of the entire project is ₹3,200 crore (US$438 million).[7]


Prime Minister Narendra Modi inaugurating the Atal Tunnel in Manali, Himachal Pradesh on 3 October 2020. Along with Rajnath Singh, Jai Ram Thakur and Bipin Rawat

Prime Minister Nehru discussed a rope way to Rohtang Pass with local tribes in 1960. Almost 39 years after, when Atal Bihari Vajpayee became the Prime Minister, locals suggested his childhood friend Arjun Gopal visit him to talk about Rohtang Tunnel. Gopal and two companions, Chhering Dorje and Abhay Chand, moved to Delhi. After a year of discussions, Vajpayee went to Lahaul in June 2000 and declared that the Rohtang Tunnel would be constructed.[8] RITES conducted a feasibility study.

Atal Tunnel Approach Inauguration 26 May 2002 - Atal Bihari Vajpayee, PM of India and Lt. Gen. Prakash Suri, Director General Border Roads (DGBR)
The commissioning of the access road construction for the Atal Tunnel by Atal Bihari Vajpayee on 26 May 2002

In 2000, the project was estimated to cost ₹500 crore and be completed in seven years.[9] On 26 May 2002, the Border Roads Organisation (BRO), a tri-service organisation of the Defence Ministry specialising in road and bridge construction in difficult terrains, headed by Lt. Gen. Prakash Suri, PVSM, was put in charge of construction.[10] The approach road to the tunnel entrance was inaugurated by Atal Bihari Vajpayee.

However the project did not move beyond the tree-felling stage by May 2003. By December 2004, the cost estimate had grown to ₹900 crore.[11] In May 2007, the government of Dr. Manmohan Singh awarded the contract to SMEC (Snowy Mountains Engineering Corporation) International Private Limited, an Australian company, and the completion date was revised to 2014. However, there was no progress for the next three years, until May 2010.[12]

Finally, the Cabinet Committee on Security in UPA government cleared the Rohtang Tunnel Project. The work was awarded to a joint venture of AFCONS Infrastructure Limited, an Indian construction company of Shapoorji Pallonji Group, and STRABAG AG, Austria, in September 2009.[13] The drilling of the Rohtang Tunnel through the Himalayan ranges began on 28 June 2010 at the South Portal, 25 km (16 mi) north of Manali. Some of the anchoring and slope stabilisation work was subcontracted to Spar Geo Infra Pvt Ltd.

Prime Minister Narendra Modi renamed the tunnel as the Atal Tunnel, in honour of Shree Atal Bihari Vajpayee, on 25 December 2019, Vajpayee's birthday.[8]

The Rohtang Tunnel has been planned to ensure an all-seasons, all-weather road route to strategically important areas of Ladakh and the remote Lahaul-Spiti valley. However, the tunnel will provide this connectivity only up to Darcha, north of Keylong in the Lahaul region of Himachal Pradesh. Connectivity to Ladakh will require more tunnels: either at Shikun La, or at the passes located on the present Leh-Manali road.


Total length of tunnel is 9.02 km.

  • The project was announced by the then Prime Minister Atal Bihari Vajpayee on 3 June 2000. The work was entrusted to BRO on 6 May 2002.[14]
  • The foundation stone of the project was laid on 28 June 2010 by Sonia Gandhi in her capacity as the Chairperson of National Advisory Council.[15]
  • As of June 2012, two years after the start of the project, 3.5 km of the tunnel digging had been completed.[16]
  • Only a little progress was made in the next one year due to heavy ingress of water at serri nullah fault zone, that required constant dewatering and slowed the digging and blasting to a crawl.
  • As of October 2013, a little more than 4 km of the tunnel had been dug. However, about 30 m portion of the roof of the tunnel collapsed towards the north portal on 17 October 2013 and the digging had to be stopped.[17]
  • As of September 2014, 4.4 km of the tunnel, i.e., half of 8.8 km planned length had been dug.[18][19]
  • As of December 2016, 7.6 km of the tunnel digging had been completed. Excavation was expected to be completed in 2017, with opening in the second half of 2019.[20][21]
  • As of 3 September 2017, 276 metres of the tunnel digging work remained.[22] Tunnel to be opened for emergency services such as Ambulances and Fire engines by the winter.[23]
  • As on 13 October 2017 both ends of the tunnel met. The Defence Minister, Nirmala Sitharaman, visited the site on 15 October 2017.[24][25]
  • As on 22 November 2017, it was decided to allow patients to be carried through the under-construction tunnel only in the gravest of emergency when the helicopter service was not available and not to allow civilians to enter the tunnel before completion due to risks of falling rocks, lack of oxygen in the tunnel as ventilation system was yet to be installed, etc. and likely interruption in construction work due to presence of civilians.[26]
  • Sep 2018: the tunnel was used for evacuation of people stranded in Lahaul after sudden spell of bad weather blocked Rohtang La due to snowfall.[27]
  • Jan 2019: 90% work completed.
  • Oct 2019: 100 metres work yet to be finished. To be opened for emergency traffic by Oct-2019 end. To be opened for general traffic by Sep-2020.[28]
  • Nov 2019: Bus service trial started through the yet-incomplete tunnel on 17 November 2019.[29] A Himachal Road Transport Corporation bus carrying 44 passengers entered tunnel from the south portal and the passengers alighted at the north portal. The bus service operated for next five winter months for residents of Lahaul and Spiti valleys. Private vehicles were not allowed through the tunnel.[30]
  • Dec 2019: On 25 December the tunnel, which was known as Rohtang tunnel till then, was officially renamed as the Atal Tunnel.
  • Sept 2020: 100% completion of project.
  • Oct 2020: The tunnel was inaugurated by the Prime Minister, Narendra Modi on 3 October 2020, in the presence of Minister of Defence, Rajnath Singh and Chief Minister of Himachal Pradesh, Jai Ram Thakur and Minister of State for Finance, Anurag Thakur.


The most challenging task was to continue the excavation during heavy snowfall in winter. Excavation for tunnelling was done from both ends. However, as Rohtang pass closes during the winter, the north portal was not accessible during winter and the excavation was being done only from the south portal in winters. Only about one-fourth of the entire tunnel was excavated from the north end and three-fourths was excavated from the south end. There were more than 46 avalanche sites on approaches to the tunnel.[31]

Other challenges to the progress of the tunnel included difficulties in disposing more than 8 lakh m³ of excavated rock and soil,[32] heavy ingress of water (as much as 30 lakh litres per day in June 2012)[33] that required constant dewatering, costlier treatment and slowed the progress of excavation from 5-metre per day to just half a metre a day and unstable rocks that slowed blasting and digging.[34] A cloud-burst and flash flood on 8 August 2003 killed 42 labourers who were building the temporary access road.[35] Questions were also raised on the impact of cutting down more than 700 trees on the ecology.[36]


The tunnel is intended to create an all-weather route to Leh and Lahaul and Spiti valleys in Himachal Pradesh.

Salient features of the Atal Tunnel are as follows:

  • Length: 9.02 km (5.6 mi)
  • Shape (cross-section) of Tunnel: Horseshoe
  • Finished width: 10.00 m (32.8 ft) at road level. (8m pavement and 1m footpath on both sides)
  • General altitude of the tunnel: 3,000–3,100 m or 9,840–10,170 ft
  • Designated vehicular speed: 80 km/h (50 mph)
  • Geology of tunnelling media: Uniformly dipping alternate sequence of quartzites, quartzitic schists, quartz-diolite-schist with thin bands.
  • Tunnel boring machines were not used because of the inability to see inside the mountain, instead blasting and digging used to build the tunnel.[37]
  • Temperature variation in the area: 25–30 °C (77–86 °F) during May–June, −30 to −20 °C (−22 to −4 °F) during Dec–Jan.
  • Overburden: Maximum 1,900 metres (6,230 ft), average more than 600 m (1,970 ft)
  • Construction technique: Drill & Blast with NATM
  • Support system: Fibre-reinforced concrete (100–300mm or 0–10 inch thick) combined with rock bolt (26.50mm dia, 5,000–9,000mm or 200–350 inch long) has been used as the principal support system. In areas of poor rock condition, yieldable steel ribs (ISMB 150/ISMB 300) have been used.
  • Tunnel ventilation: Semi-transverse system of ventilation.
  • A 2.25 m high and 3.6 m wide emergency tunnel is integrated in the tunnel cross-section beneath the main carriageway.

The following parameters have been set in design:

  • (a) Upper tolerance limit for concentration – 150ppm
  • (b) Visibility factor – 0.009/m
  • (c) Vehicles
  • (i) Cars – 3000 Nos.
  • (ii Trucks – 1500 Nos.
  • (d) Peak hour traffic – 337.50 PCUs
  • (e) Design vehicular speed in Tunnel
  • (i) Maximum Speed – 80 km/h (50 mph)
  • (ii) Minimum Speed – 30 km/h (19 mph)

Project Cost : Approximately ₹3,200 crore[38]

Safety measures

The tunnel was built using the New Austrian tunnelling method and has been equipped with a semi-transverse ventilation system, where large fans separately circulate air throughout the tunnel. A 2.25 m tall and 3.6 m wide emergency tunnel has been integrated into the tunnel cross-section beneath the main carriageway for evacuation during emergencies.

Fires inside the tunnel will be controlled within an area of 200 metres and fire hydrants are provided at specific locations throughout the tunnel.The tunnel also has a public announcement system to make important announcement in emergency situations for which loudspeakers are installed at regular intervals.

Heavy snowfall in the Rohtang Pass area is a major concern, especially on the approach roads to the main tunnel. To prevent any damage to the roads and to ensure the safety of the roads and tunnel users alike, avalanche control structures have been constructed. Since the Atal tunnel is likely to witness heavy traffic, CCTV cameras are placed at regular intervals in the tunnel which are connected to two monitoring rooms on both ends of the tunnel for vehicular management and pollution monitoring. Pollution sensors continuously monitor the air quality in the tunnel and if the air quality in the tunnel is below the desired level, fresh air is injected into the tunnel via two heavy duty fans on each side of the tunnel.



See also


  1. ^ "Atal Tunnel renamed as 'Atal Tunnel, Rohtang'". The Times of India. 13 August 2020. Retrieved 13 August 2020.
  2. ^ "Atal Tunnel renamed as 'Atal Tunnel, Rohtang'". The Times of India. 13 August 2020. Retrieved 13 August 2020.
  3. ^ News, Indian Defence. "9-km-long Atal Tunnel an engineering marvel". Indian Defense News, Indian Armed Forces, IDRW, Defence. Retrieved 3 October 2020.
  4. ^ "Atal Tunnel: How world's longest tunnel above 10,000 feet at Rohtang pass will make use of automation solutions". 1 October 2020.
  5. ^ "Importance of Rohtang Tunnel for Lahaul & Pangi resident". The News Himachal. Retrieved 29 July 2012.
  6. ^ "Explained: What is the strategic importance of Atal Tunnel at Rohtang?". The Indian Express. 29 August 2020. Retrieved 29 August 2020.
  7. ^ "World's longest highway tunnel opened in Himachal Pradesh". The Hindu. Special Correspondent. 3 October 2020. ISSN 0971-751X. Retrieved 4 October 2020.CS1 maint: others (link)
  8. ^ a b Cabinet nod for water scheme, renaming of tunnel after Vajpayee, The Hindu, 24 December 2019.
  9. ^ "PM reiterates desire for peace with Pak". 7 June 2000. Retrieved 12 January 2012.
  10. ^ "PIB Press Releases". Retrieved 3 October 2020.
  11. ^ "Construction of Rohtang Tunnel". 2 December 2004. Retrieved 12 January 2012.
  12. ^ "Rohtang tunnel work likely to start next month". 16 July 2009. Archived from the original on 25 January 2013. Retrieved 12 January 2012.
  13. ^ "Afcons Infrastructure : Partners". Archived from the original on 27 December 2011. Retrieved 12 January 2012.
  14. ^ "Engineering marvel: India's highest tunnel to see light of day in October". Hindustan Times. 11 September 2017. Retrieved 3 October 2020.
  15. ^ "Engineering marvel: India's highest tunnel to see light of day in October". Hindustan Times. 11 September 2017.
  16. ^ "Rivulet gushes out during Rohtang tunnel digging". The Pioneer. India. 5 June 2012. Retrieved 17 June 2012.
  17. ^ "Part of Rohtang Tunnel Collapses". 19 October 2013.
  18. ^ "BRO Annual Chief Engineers' Conference 2014 : A Curtain Raiser".
  19. ^ "Rohtang tunnel may not be ready before 2019 | Shimla News - Times of India". The Times of India.
  20. ^ "Rohtang Tunnel Records Best Yearly Progress in 2016 - Hill Post".
  21. ^ "Rohtang tunnel project: Defence ministry checks Rohtang Tunnel progress | Shimla News - Times of India". The Times of India.
  22. ^ "rohtang: Defence ministry official visits Rohtang tunnel | Shimla News - Times of India". The Times of India.
  23. ^ "Medical transit via Rohtang tunnel this winter? | Shimla News - Times of India". The Times of India.
  24. ^ "रोहतांग टनल का निरीक्षण करने पहुंच रहीं रक्षा मंत्री, बीआरओ अधिकारियों के साथ करेंगी बैठक". Amar Ujala.
  25. ^ "Himachal polls-2017: Quiet opening to Rohtang tunnel amid election din". 28 October 2017.
  26. ^ "Rohtang tunnel to be used only in severe medical emergency | Chandigarh News - Times of India". The Times of India.
  27. ^ Service, Tribune News. "210 rescued from Koksar, Lahaul valley". Tribuneindia News Service.
  28. ^ "'Rohtang tunnel to open for traffic by September 2020' | Shimla News - Times of India". The Times of India.
  29. ^ Service, Tribune News. "HRTC starts bus via Rohtang tunnel". Tribuneindia News Service.
  30. ^ "HRTC launches bus service across Rohtang tunnel".
  31. ^ "8.8-km tunnel to make Leh accessible in all seasons". The Times of India. 2 January 2007.
  32. ^ "Latest News, Breaking News Live, Current Headlines, India News Online - The Indian Express". The Indian Express.[permanent dead link]
  33. ^ Vijay Mohan (9 July 2012). "Unexpected water ingress delays boring of Rohtang Tunnel". The Tribune. Chandigarh. TNS. Retrieved 29 July 2012.
  34. ^ "Water ingress, loose rocks delay boring of Rohtang tunnel - The Times of India". The Times of India.
  35. ^ "60 washed away in Kulu flash floods". The Tribune. Chandigarh. 9 August 2003. Retrieved 12 January 2012.
  36. ^ "Rohtang tunnel to affect area ecology, warn experts". The Tribune. Chandigarh. 11 August 2003. Retrieved 12 January 2012.
  37. ^ Polgreen, Lydia (31 July 2010). "India Digs Under Top of the World to Match Rival". The New York Times. Retrieved 12 January 2012.
  38. ^ "Atal Tunnel: World's longest highway tunnel above 10,000 feet, connecting Manali to Leh, completed in 10 years". The Financial Express. 16 September 2020. Retrieved 6 October 2020.
  39. ^ "City News, Indian City Headlines, Latest City News, Metro City News". The Indian Express.
  40. ^ "Timeline of sequence of events at Atal Tunnel Project". Discover Kullu Manali. Retrieved 13 July 2020.
  41. ^ Bisht, Gaurav (1 October 2020). "After Rohtang, more high-altitude tunnels to come up on Manali-Leh highway". Hindustan Times. Retrieved 5 October 2020.

External links