MUM 4 at Mahape 2 is listed by Nxtra by Airtel at 42 MW of IT power across 3,600 racks — 11.7 kW a rack, with a declared PUE below 1.55. It is the largest single building in Nxtra’s Mumbai cluster. The interesting part is what sits behind it. In 2021 this 600,000 square foot, three-tower park was announced at 58 MW across 7,500 racks. It now carries 60 MW across 5,200 racks — the same steel, 31% fewer cabinets, and 49% more power in each one. That is the AI transition in Indian data centres, documented in one site.
1At a glance
2The same park, replanned
Almost every record in this registry compares an announcement with nothing. This one compares two versions of the same engineering plan, five years apart, and the difference is the whole industry’s direction of travel.
| Measure | 2021 plan | Listed 2026 | Change |
|---|---|---|---|
| IT power across the park | 58 MW | 60 MW | +3% |
| Racks across the park | 7,500 | 5,200 | −31% |
| Power per rack | 7.7 kW | 11.5 kW | +49% |
| Built-up area | 600,000 sq ft | 600,000 sq ft | unchanged |
| Design PUE | below 1.5 | below 1.55 | slightly worse, and honestly so |
Read the first three rows together and the meaning is unambiguous. Nxtra did not build a bigger park. It built the same park for different equipment: 2,300 fewer cabinets, each carrying half again as much power. A design that in 2021 assumed cloud and enterprise servers at 7.7 kW a cabinet is now being filled at 11.5 kW, which is where accelerated computing starts.
The PUE moving from below 1.5 to below 1.55 is the honest cost of that change. Denser equipment is harder to cool, and pretending otherwise would be a marketing number. A 0.05 increase in PUE on 60 MW is roughly 3 MW of additional overhead load — a building’s worth of power spent on cooling the same compute.
For anyone forecasting Indian capacity, this is the most useful data point in the registry. When an operator replans for AI, the megawatt number stays roughly constant and the rack number falls. Markets that forecast capacity in racks are therefore forecasting the wrong quantity.
A cabinet in a 2021 Indian design carried 7.7 kW. In the same building today it carries 11.5 kW. The next generation is being specified at 100 kW and above.
Every forecast built on rack counts has already been overtaken by this shift.
3What 42 MW in one building means
Forty-two megawatts in a single facility is large for India and it puts this building in a different class from the rest of the portfolio.
| Building | MW | Racks | kW a rack | Position |
|---|---|---|---|---|
| MUM 4 — Mahape 2 | 42 | 3,600 | 11.7 | the largest and densest |
| MUM 3 — Mahape 1 | 18 | 1,600 | 11.3 | sibling, same park |
| Siruseri DC 3, Chennai | 27 | 5,400 | 5.0 | large but conventional |
| MUM 2 — Airoli | 7 | 1,100 | 6.4 | legacy |
| MUM 1 — Chandivali | 4 | 600 | 6.7 | legacy |
MUM 4 alone is 59% of Nxtra’s 71 MW Mumbai cluster and about 17% of the 250 MW the company reports nationally on its annual report basis. It is also, on the density test, the only building in the estate that could host a modern accelerated-computing tenancy without a rebuild.
That concentration is worth stating plainly for a supplier: if you sell cooling or power distribution to Nxtra in Mumbai, this building is more than half your addressable opportunity in the city. The other 29 MW are legacy halls at 5 to 7 kW a rack that buy refresh, not transformation.
4Not the same as BOM1
At least one widely-read directory entry merges this park with a neighbouring project. The two are different companies and different buildings, and the error is worth correcting in public.
| Item | Nxtra Mumbai III / MUM 3–4 | Digital Edge BOM1 |
|---|---|---|
| Owner | Nxtra Data, Bharti Airtel | Digital Edge, with NIIF |
| Site | Mahape / Thane-Belapur corridor | a 47-acre campus in the same Navi Mumbai belt |
| Scale announced | 58 MW across 7,500 racks, since replanned | about 300 MW at full build on the campus |
| Investment | part of a ₹5,000 crore national programme | $2 billion campus, per reporting |
| First phase | three towers, 600,000 sq ft | BOM1, completed in late 2025 |
| The directory error | one listing attributes the $2 billion and 47-acre figures to Nxtra’s park | — |
The conflation is understandable — same corridor, same year, both describe a three-letter building code next to a large number — and it is exactly the kind of error that propagates into market sizing. Two campuses of 300 MW and 60 MW became one campus of $2 billion in at least one database.
Gridvik records Nxtra’s Mahape park at 60 MW across 5,200 racks, the sum of the operator’s two published cards, and does not attribute Digital Edge’s site, capital or capacity to it.
5The Mumbai cluster, complete
With both Mahape halls counted, Nxtra’s Mumbai cluster is fully mapped for the first time in this registry.
| Facility | MW | Racks | Share of cluster |
|---|---|---|---|
| MUM 4 — Mahape 2 | 42 | 3,600 | 59% |
| MUM 3 — Mahape 1 | 18 | 1,600 | 25% |
| MUM 2 — Airoli | 7 | 1,100 | 10% |
| MUM 1 — Chandivali | 4 | 600 | 6% |
| Total | 71 MW | 6,900 | 100% |
Seventy-one megawatts and 6,900 racks. On the 250 MW national figure that is about 28% of the platform in one city, and 85% of it is in two buildings on one corridor. For a vendor, that is a remarkably simple targeting problem: two addresses, one procurement function, and a stated ambition to reach 1 GW nationally.
6Timeline
- Airtel announces a ₹5,000 crore, 400 MW expansion of Nxtra. The Navi Mumbai park is described as 58 MW of IT power and 7,500 racks across three towers of 600,000 square feet, with a design PUE below 1.5
- The first Nxtra Mumbai III buildings are brought into service. Third-party records date the site to 2025 with expansions through 2026
- Airtel announces a $1 billion investment in Nxtra and describes a platform of about 300 MW going to 1 GW, with Mumbai as the focus of land acquisition
- The operator lists MUM 4 at 42 MW of IT power across 3,600 racks with a declared PUE below 1.55, and MUM 3 at 18 MW across 1,600 racks
- No commissioning date, occupancy figure or tenant name has been published for either Mahape building
7Procurement
8Limits and open questions
9Sources
Sources: Nxtra Mumbai data centre page, Nxtra by Airtel site, Airtel December 2021 expansion release, Airtel March 2026 investment release, Baxtel facility records, DataCenterMap, DataCenterHawk, Airtel FY26 annual report.