DG set permission on a construction site does not come as one certificate. The set must already carry type approval under the emission rules notified as GSR 804(E) in November 2022, and a noise approval up to 1,000 kVA. The wiring is self-certified to your state’s Electrical Inspector or inspected by that Inspector before switch-on, depending on the voltage and generating capacity your state has notified. The State Pollution Control Board comes in through your project’s consent, and directly from 1 MVA of diesel gensets. The stack follows the CPCB formula H = h + 0.2 × √kVA.

There is no single “DG set NOC”, though contractors ask for one all the time. The paperwork sits with three offices and a label on the canopy, and the thresholds move with the size of the set. Until the grid connection arrives, that set runs your tower crane and site lighting, so get it right before the first inspection.

DG set permission by capacity: who approves what

Set or site What applies Who to approach
Any new diesel genset engine up to 800 kW Type approval and conformity of production under GSR 804(E), in force from 1 July 2023 The dealer or rental firm must show the certificates; CPCB is the nodal agency
Diesel set up to 1,000 kVA made on or after 1 January 2005 75 dB(A) at 1 metre from the enclosure, integral acoustic enclosure, noise type approval Dealer or rental firm; State Pollution Control Board enforces
Other diesel sets, including those above 1,000 kVA Acoustic enclosure or treated room with at least 25 dB(A) insertion loss, plus a 25 dB(A) exhaust muffler State Pollution Control Board
Installation at or below the voltage your state has notified Work by a licensed electrical contractor; owner self-certifies and files the report before switching on State electrical inspectorate
Above the notified voltage, or a generating unit above the capacity the state notifies Electrical Inspector inspects and tests before supply starts State electrical inspectorate
Total genset capacity of 1 MVA or more on diesel Orange category in CPCB’s 2025 classification State Pollution Control Board

The rows stack: one set usually falls in three or four of them.

The emission rule: type approval under GSR 804(E)

The environment ministry notified GSR 804(E) on 3 November 2022, setting new emission limits for genset engines up to 800 kW from 1 July 2023. For the 56 to 560 kW band, where most site sets fall, the particulate limit is 0.02 g/kWh.

The line that matters to a site owner is General Condition 3: “No person shall sell, import or use an engine and genset for power generation application which is not having a valid Type Approval certificate and certificate of Conformity of Production.” ARAI, ICAT and the Indian Institute of Petroleum issue the certificates, and CPCB lists the current genset notifications.

Gensets to the earlier norms could be manufactured until 31 December 2023, and GSR 436(E) of 14 June 2023 let sets ordered by 30 June 2023 be supplied until 30 June 2024. A set bought new after that should meet the 2022 norms. For an older rental set, ask for its certificate and date of manufacture. CPCB, the Commission for Air Quality Management and the State Boards may also set stricter local norms.

Noise limits and the acoustic enclosure

A diesel set of up to 1,000 kVA made on or after 1 January 2005 must not exceed 75 dB(A) at 1 metre from the enclosure surface, with the enclosure fitted at the factory. Its conformance label must show the 75 dB(A) limit, the type approval certificate number and the date of manufacture. Read it before the set leaves the yard.

Sets outside that rule, including anything above 1,000 kVA, are controlled at the user’s end: an acoustic enclosure or treated room with at least 25 dB(A) insertion loss, and an exhaust muffler of at least 25 dB(A). Sets above 250 kVA may travel dismantled, and the State Board checks noise after reassembly on site.

Stack height for a DG set: the CPCB formula

GSR 804(E) says genset stack height “shall be governed as per Central Pollution Control Board guidelines”. That guideline, quoted in a joint committee report the National Green Tribunal reproduced in 2022, is H = h + 0.2 × √kVA, where H is the total stack height in metres, h is the height of the nearest building and kVA is the total capacity of the set.

Set capacity 0.2 × √kVA Stack height next to a 15 m building
62.5 kVA 1.6 m 16.6 m
125 kVA 2.2 m 17.2 m
250 kVA 3.2 m 18.2 m
500 kVA 4.5 m 19.5 m
1,000 kVA 6.3 m 21.3 m

On a site, the nearest building may be your own structure, and it grows every month. Ask the board which height it will measure against while the frame is rising.

Engines above 800 kW follow a separate standard: the stack is the highest of 14Q0.3 (Q is sulphur dioxide in kg per hour), 6 metres above the building, or 30 metres.

Short stacks do get caught. In Satish Govind v. President and Secretary, Windsor Park Residents Welfare Association, a joint committee recorded the stack height of a Ghaziabad housing society’s DG sets as inadequate. On 1 November 2022 the Tribunal directed that sets over 15 years old be discarded and “replaced by equipments run on cleaner fuel and compliant with norms including proper stack height”.

Electrical safety: self-certification or the Electrical Inspector

The wiring falls under the CEA (Measures relating to Safety and Electric Supply) Regulations, 2023. Regulation 31 requires an electrical contractor licensed by the State Government, working under a person holding a certificate of competency.

Regulation 45 splits installations by voltage. At or below the voltage your state has notified, the owner tests and self-certifies before supply starts and sends the report to the Electrical Inspector; if it is not acknowledged within three working days, it is deemed received.

Above that voltage, and for generating units above the capacity set under regulation 34, the Electrical Inspector inspects and tests first. Regulation 34 gives no number; the appropriate government notifies it, which for a private site is your state. Periodic checks under regulation 32 follow the state’s cycle, capped at five years.

For scale, CEA’s own inspectors, who cover central government and Union Territory installations, approve generating plants above 500 kVA and installations above 11 kV. Your state’s numbers may differ.

If the inspection or the noise check says your old set has to go, a type-approved replacement is a capital purchase like any machine; compare equipment finance options before you commit to another season of rent.

When the pollution control board comes in

CPCB’s classification of 12 February 2025 puts standalone gensets of 1 MVA or more in total on liquid fuel in Orange, and on gas in Green. Gensets below 1,000 kVA “may not require additional classification”, but a White or Green unit with higher-category gensets moves up a category.

Building construction projects of 20,000 square metres or more of built-up area are themselves Orange, with consent to establish and operate “to be taken as per EC conditions, as applicable”. List the DG sets in that application. How the two consents work, and what to ask the board in writing, is set out in consent to establish and consent to operate.

What to ask in Maharashtra, Gujarat or Madhya Pradesh

The central rules leave the numbers to the states. Before you mobilise, write to the state electrical inspectorate and the regional office of the Maharashtra, Gujarat or Madhya Pradesh Pollution Control Board. Ask:

  • the voltage notified for self-certification, and the generating capacity notified under regulation 34
  • the forms, fee and usual time for self-certification or inspection
  • whether your project’s consent covers the DG set or the set must be added to it
  • which building the board treats as h in the stack formula on a rising site
  • any local restriction on DG set hours or fuel

Keep the replies on file. State fees are not quoted here because they differ and change.

NCR winters, the fuel tank and the fire NOC

In Delhi NCR, the winter Graded Response Action Plan adds genset rules by capacity and fuel, set out in GRAP restrictions on construction equipment. Bulk diesel on site has its own licensing line, explained in diesel storage licence for a site. Fire safety is a separate approval again, covered in fire NOC for construction site work.

The bottom line

DG set permission comes in layers. Hire or buy a type-approved set with its label intact, build the stack to the CPCB formula, have a licensed contractor wire it, file the self-certification or call the Electrical Inspector as your state requires, and keep the set inside your State Board consent.

Once the site is powered and compliant, look for the next job in the tender and project opportunities listings.

Rates, schemes, specifications and prices change — confirm current terms with the OEM, dealer, bank or insurer before deciding. Notified voltages, generating capacities, consent categories and fees are set by each state; confirm them with your state electrical inspectorate and State Pollution Control Board before installing a DG set.