Poisoned Wells

Examining the scale of DNS censorship in India

View the project website here.

This repository contains the data and documentation for Poisoned Wells, a large-scale survey of DNS censorship across 6 major Indian Internet Service Providers (ISPs).

Accessing the data

1. Interactive explorer

Visit dnsblocks.in/#explorer to explore the full dataset of 43,083 blocked domains using the interactive web interface.

Features:

• Filter by ISP
• Search specific domains
• Filter by domain category
• Filter by Top-Level Domain (TLD)
• Sort by Tranco popularity ranking
• Toggle between "blocked by ANY", "blocked by ALL", or "blocked exclusively by"

2. Compiled blocklist (CSV)

File: data/compiled_blocklist.csv Size: 1.6 MB Format: CSV with headers

Contains all 43,083 blocked domains with:

• Domain name
• Category
• Tranco popularity rank
• Blocking status for each of the 6 ISPs

Example row:

domain,category,tranco_rank,ACT,AIRTEL,CONNECT,JIO,MTNL,YOU
0-123movies.com,MOV,-,0,1,0,0,0,0

Blocking status values:

• 1 = Blocked
• 0 = OK/Not blocked
• Other values: TIMEOUT, NXDOMAIN, SERVFAIL, REFUSED, ERROR

3. Raw DNS measurements

Total size: ~68 GB compressed, ~760 GB uncompressed Format: Compressed jsonl files (one per ISP) Contains: 1.76 billion DNS measurements

Measurements include query domain, response code, response IPs, timestamp (and additional records in some cases.)

View download links and detailed format here.

Dataset overview

ISPs covered

Full Name	ASN
Atria Convergence Technologies	AS18209
Bharti Airtel	AS9498
Connect Broadband	AS17917
Reliance Jio	AS55836
Mahanagar Telephone Nigam Ltd.	AS17813
You Broadband	AS18207

Categories

The blocklist uses categories based on an expanded version of Citizen Lab's test list taxonomy.

View full category definitions here.

Citation

If you use this data or research in your work, please cite:

For the dataset:

@misc{poisonedwellsdata,
  author = "Karan Saini",
  title  = "Compiled blocklist and DNS measurement data from the Poisoned Wells project",
  year   = "2026",
  month  = "March",
  url    = "https://github.com/qurbat/dnsblocks.in/tree/main/data"
}

For the report:

@misc{poisonedwellsreport,
  author = "Karan Saini",
  title  = "Poisoned Wells: Examining the scale of DNS censorship in India",
  year   = "2026",
  month  = "March",
  url    = "https://dnsblocks.in"
}

License

All data (compiled block list and raw DNS measurements) is released under the Creative Commons BY-NC-SA 4.0 license.

Acknowledgments

This research was supported by:

• Open Technology Fund - through the Information Controls Research Program
• Internet Governance Project - host organization at the Georgia Institute of Technology's School of Public Policy, providing institutional support and technical guidance

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