TRAI Coastal Drive Test in Sundarbans Highlights Strong 5G Performance by Private Operators, Persistent Gaps for BSNL

While Airtel and RJIL achieved perfect call connectivity, BSNL recorded a severely low success rate, indicating major voice connectivity challenges in the coastal stretch.

 

The Telecom Regulatory Authority of India (TRAI) has released findings of its Independent Drive Test (IDT) conducted along the coastal river routes of Herobhanga, Bidyadhari and Datta in the Sundarban region of West Bengal in January 2026.

The assessment, carried out under the supervision of TRAI’s Regional Office in Kolkata, aimed to evaluate real-world mobile network performance across village residential areas, tourist spots and local commercial hubs in one of India’s ecologically sensitive and geographically challenging regions.

Scope of Testing

On 29 January 2026, TRAI teams conducted:

• 41.0 km of coastal drive testing

• 1 hotspot location test

Technologies evaluated included 2G, 3G, 4G and 5G, capturing user experience across multiple handset capabilities. The findings have been communicated to the concerned telecom service providers (TSPs).

The drive test covered key areas including:

• Jharkhali

• Amlamethi

• Sajnekhali

• Sonagar

• Gadkhali

Static testing was conducted at Jhore Jole Jongole – Eco Heritage Resort, Jharkhali, a prominent tourist location.

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Voice Services Performance

Call Setup Success Rate (CSSR)

In auto-selection mode (5G/4G/3G/2G):

• Airtel: 100.00%

• BSNL: 18.37%

• RJIL (Jio): 100.00%

• VIL (Vodafone Idea): 91.61%

While Airtel and RJIL achieved perfect call connectivity, BSNL recorded a severely low success rate, indicating major voice connectivity challenges in the coastal stretch.

Drop Call Rate (DCR)

• Airtel: 0.00%

• BSNL: 8.89%

• RJIL: 0.68%

• VIL: 0.00%

BSNL experienced the highest drop call rate among operators.

Call Setup Time (CST)

• Airtel: 1.91 seconds

• BSNL: 7.20 seconds

• RJIL: 0.75 seconds (fastest)

• VIL: 1.53 seconds

RJIL recorded the quickest call setup time, while BSNL’s setup time was significantly higher.

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Data Services Performance

Overall Average Download Speeds

• Airtel (5G/4G): 58.81 Mbps

• BSNL (4G/3G/2G): 3.24 Mbps

• RJIL (5G/4G): 60.40 Mbps

• VIL (4G/2G): 21.65 Mbps

RJIL delivered the highest overall average download speed at 60.40 Mbps, closely followed by Airtel.

Overall Average Upload Speeds

• Airtel: 8.33 Mbps

• BSNL: 3.58 Mbps

• RJIL: 17.49 Mbps

• VIL: 6.60 Mbps

RJIL led in upload performance.

Latency (50th Percentile)

• Airtel: 69.83 ms

• BSNL: 154.01 ms

• RJIL: 34.79 ms (lowest)

• VIL: 47.97 ms

RJIL demonstrated the lowest latency, supporting better performance for real-time applications.

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5G Performance

The drive test recorded:

• Maximum average 5G download speed: 60.40 Mbps

• Maximum average 5G upload speed: 17.49 Mbps

These figures reflect moderate but stable 5G performance in a geographically complex coastal environment.

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Hotspot Performance (Mbps)

At the tested hotspot location:

Airtel

• 4G Download: 5.81

• 4G Upload: 4.76

RJIL

• 4G Download: 17.86

• 4G Upload: 4.92

• 5G Download: 24.10

• 5G Upload: 5.73

Notably, download and upload tests failed in:

• Airtel 5G

• BSNL 4G

• VIL 4G

This indicates localized network instability at the hotspot location.

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Signal Strength Observations

Poor signal strength during voice testing was observed over portions of the route:

• Airtel: 4.27%

• BSNL: 25.81%

• RJIL: 9.64%

• VIL: 11.74%

During data testing:

• Airtel: 24.44%

• BSNL: 24.81%

• RJIL: 25.95%

• VIL: 11.76%

While BSNL showed weak coverage in voice services, data signal strength challenges were observed across multiple operators in the coastal terrain.

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Key Takeaways

• Airtel and RJIL delivered strong and consistent voice performance.

• RJIL led in data download speeds and latency performance.

• BSNL faced significant voice reliability and latency challenges.

• 5G performance was present but moderate given the remote geography.

• Data signal strength variability indicates infrastructure constraints in the coastal ecosystem.

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Regulatory Oversight

The tests were conducted using TRAI-specified equipment and standardized real-time testing protocols. The detailed report is available at www.trai.gov.in.

For further information, Shri Kaushik Mukherjee, Advisor (Regional Office, Kolkata), TRAI, may be contacted at adv.kolkata@trai.gov.in or +91-33-22361401.

The findings aim to inform consumers and encourage telecom operators to strengthen connectivity in remote and ecologically sensitive regions like the Sundarbans.