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Iron Mountain MUM-3 data center

Navi Mumbai, Maharashtra, India · Mumbai metro market · location approximate to district level

Iron Mountain MUM-3 is a data center project in Navi Mumbai, India, operated by Iron Mountain Data Centers (Web Werks JV). It is under construction. It is planned for 85 MW of IT load.

Latest change on record: moved to under construction in January 2026.

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Stage
Under construction
Planned IT load
85 MW
Running now
Not disclosed
Operator
Iron Mountain Data Centers (Web Werks JV)
Joint venture
AI workloads
Likely
Evidence grade
Corroborated
Will it get built?Strong6 of 7 gates passed
✓ Land secured✓ Power arranged✓ Approvals granted✓ Money committed✓ Tenant or own use○ Builder appointed✓ Construction started

Next gate to watch: Builder appointed.

Your call. Will it be built?

Build odds is ArusGrid's reading of the public record, not a forecast, a rating or advice. It counts the gates this project has passed in public sources. Private progress does not show, a passed gate can be undone, and projects that pass every gate still stop. The method has not yet been tested against outcomes. How it works.

How India approves, powers and taxes data centers is on Data center rules in India.

How well evidenced is it

Construction or financing is evidenced, or several independent signals agree. On record: named funder, disclosed client (confirmed), dated, sized phase, three or more sources, dated source in the last 24 months. Criteria.

AI workloads

StatusLikely

Operator describes hyperscale-ready capacity; 85MW greenfield.

Access to AI chips

GradeNo US licence required

This country carries no US destination-based licence requirement for advanced AI chips as the rules are enforced today. Access is a commercial matter between the project and its vendors. Criteria.

Phases

MUM-3 · Under construction85 MW, target 2028

Stage history

2023-06-09Announced · telecomtalk.info
2026-01Under construction · w.media

Who is behind it

OperatorIron Mountain Data Centers (Web Werks JV) · Joint venture
Funder, Joint venture partnerIron Mountain
Funder, Joint venture partnerWeb Werks

Who uses the compute

TenantUndisclosed customer (MUM-3 pre-lease) · confirmed

51.5MW pre-leased at MUM-3, which is 100% of the 51.5MW Iron Mountain lists as under construction there · as of 2026-09-30

Iron Mountain's Q3 2026 supplemental lists India MUM-3 with 51.5MW under construction and 51.5MW pre-leased (100%). The Q3 2026 earnings presentation says 51MW was leased in Mumbai. The customer is not named, and no filing says it is a hyperscaler.

Source · Supplemental Financial Information Third Quarter 2026 (Iron Mountain Incorporated (SEC Form 8-K, Exhibit 99.3), 2026-11-05)

Money at this site

ArusGrid estimate, building costabout US$480m to US$714m

No figure has been announced. This range is 85 MW of planned IT load times a published benchmark of US$6.64 per watt for Mumbai, plus or minus 15 percent, with 10 percent more at the top for liquid cooling because the project is AI-positioned. It covers the building and its mechanical and electrical plant. It excludes land, grid works, servers and fees.

Benchmark: Turner & Townsend Data Centre Construction Cost Index 2025, as reported by Data Storage Asia. An estimate is never added to any total on the site.

Land
Land sellerNot disclosed · 5 acres · Jun 2023 Confirmed source ↗
The JV said in June 2023 it had already acquired a parcel of about 5 acres in Rabale for MUM-3. The seller and terms are not named. The operator page now gives a 5.5 acre campus shared with MUM-1 and MUM-2.
Power supply
Dedicated substationunspecified (MSEDCL area) · 120 MVA · Jun 2023 Reported source ↗
Approved additional substation for the campus per the JV's 2023 release. · Applies to the whole campus.
Dedicated substation137 MVA · Oct 2026 Confirmed source ↗
The operator page gives 137MVA gross with a dedicated on-site substation for 85MW IT.
Water and cooling
CoolingHybrid air and liquid cooling Confirmed source ↗
Advanced cooling for high-density compute including liquid cooling.

Sources

  1. Mumbai Data Centers | India Colocation | Iron Mountain (Iron Mountain (operator site, accessed), 2026-09-27)
  2. Web Werks – Iron Mountain Data Centers JV to Expand Mumbai Campus With Third Facility (TelecomTalk, 2023-06-09)
  3. Iron Mountain Data Centers breaks ground on 85 MW AI DC campus in Mumbai (W.Media, 2026-01-21)
  4. Iron Mountain breaks ground on 85MW AI-ready data centre in Mumbai (Iron Mountain, 2026-02-18)
  5. IMDC Mumbai MUM-3 data center (Iron Mountain, 2026-10-18)
  6. Web Werks-Iron Mountain to invest Rs 1,400 cr to develop data center in Navi Mumbai (Web Werks, 2023-06-14)
  7. Iron Mountain Data Centers breaks ground on 85 MW AI DC campus in Mumbai (W.Media, 2026-01-21)
  8. Iron Mountain Data Centers takes over Web Werks (W.Media, 2025-04-03)
  9. Rating Rationale (CRISIL Ratings, 2026-03-27)
  10. Supplemental Financial Information Third Quarter 2026 (Iron Mountain Incorporated (SEC Form 8-K, Exhibit 99.3), 2026-11-05)
  11. Iron Mountain Incorporated (IRM) Q3 2026 Earnings Call Transcript (Earnings Whispers, 2026-11-05)
  12. Action Taken Report of 6th CAC Meeting of 2024-25 (Booklet No. 6) dtd. 03.09.2024 (Maharashtra Pollution Control Board)

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