DG Sets, Boilers and Emission Rules for Your Building or Factory

Diesel generator sets and fuel-burning boilers are among the most common sources of air pollution from buildings and factories, and they are closely regulated. Emission standards for gensets are set under the Environment (Protection) Rules, 1986, with the CPCB IV+ norms applying to new gensets up to 800 kW. Boilers and furnaces must meet the emission standards for their sector and fuel, and the conditions of their consent to operate.

In Delhi NCR, the rules are stricter. The Commission for Air Quality Management has restricted the use of DG sets and banned unapproved fuels for industry, and its Graded Response Action Plan adds further restrictions as air quality worsens. In the September 2026 revision of GRAP, actions on DG sets were moved to Stage I, the earliest stage. This page explains the rules on gensets and boilers, the NCR restrictions, the compliance options, and how to deal with enforcement.

Is this your situation?

The rules at a glance

DG sets in Delhi NCR

The Commission for Air Quality Management, set up under the CAQM Act, 2021, has issued directions on DG sets across NCR. In broad terms, these directions limit the use of DG sets to emergencies and essential services, and require larger gensets that are used to be converted to dual fuel (gas and diesel) or fitted with approved retrofit emission control devices, according to timelines and capacity bands the Commission has set. GRAP adds stage-wise restrictions as air quality deteriorates. Because these directions have been revised several times, the exact rules for your genset depend on its capacity, its use and the current CAQM direction and GRAP schedule.

For buildings, this means checking each genset's rating, its compliance with type approval norms, and whether it has been converted or retrofitted. For industries, it also means checking the fuel used in boilers and furnaces against CAQM's approved fuel list. See NCR air pollution rules.

How to stay compliant

If your DG set is sealed or you get a notice

During GRAP stages, inspection teams may seal non-compliant DG sets or issue notices, and boards can impose penalties and environmental compensation. If this happens, gather evidence of compliance: type approval certificates, conversion or retrofit certificates, running logs showing emergency use, and stack monitoring reports. Respond to the notice within the time given. If the sealing was based on a misunderstanding, for example a compliant dual-fuel set treated as diesel-only, we apply for de-sealing with the evidence. See closure notice reply.

Time and typical cost

Our fees are agreed in writing at the start, stage by stage. They are not linked to the outcome.

Documents usually needed

Laws that apply

How we work

We are a litigation and advisory practice led by Advocate BK Singh, with offices in Dwarka (New Delhi) and Vaishali (Ghaziabad). This is what you can expect:

• Equipment inventory: every genset and boiler checked.
• Current directions applied: CAQM rules and GRAP stages change often.
• Practical options: conversion, retrofit or replacement.
• Fast response to sealing: with evidence.
• Written fee terms: agreed stage by stage, never linked to the outcome.

Mistakes we see with DG sets

Dual fuel, retrofit device or replacement

Owners of older diesel gensets in NCR usually have three ways to bring them in line: convert the genset to dual fuel, so that it runs mainly on gas with a share of diesel; fit an approved retrofit emission control device that cuts particulate emissions; or replace the genset with a new one that meets the current CPCB IV+ norms. Which route makes sense depends on the genset's capacity and age, whether piped gas is available at the site, the hours the genset actually runs, and the timelines in the current CAQM direction.

Whatever route you choose, keep the paperwork. Boards and enforcement teams ask for the type approval certificate of the genset, the test certificate of the retrofit device from a recognised agency, the conversion certificate for dual fuel kits, and the logbook of running hours. A genset that has been upgraded but cannot be shown to be compliant on paper is often treated as non-compliant during a drive.

Boilers, furnaces and approved fuels

For industrial units in NCR, the larger issue is often the fuel. The Commission for Air Quality Management has banned coal and other unapproved fuels for industrial, domestic and other miscellaneous uses in the region, and published a list of approved fuels. In broad terms, approved fuels include natural gas and other gaseous fuels, and certain biomass fuels used under conditions; pet coke, furnace oil and coal are not permitted for most industrial uses. Units in industrial areas served by piped gas have been required to switch to gas.

If your boiler or furnace still runs on a fuel that is not on the list, you are exposed to closure directions during enforcement drives regardless of your consent. Check the current list and any sector-specific exceptions before buying fuel, and keep fuel purchase invoices that show what you actually burn.

The genset compliance file

Housing societies, offices and malls

Most enforcement on gensets in Delhi NCR is against buildings, not factories: group housing societies, malls, office complexes, hospitals, hotels and banquet halls. In a housing society, the maintenance agency or the RWA is usually treated as the person in charge of the gensets, and receives the notice. Because GRAP restrictions on DG sets now begin at Stage I under the September 2026 revision, a building may face restrictions early in the winter season. Buildings should plan for backup power that complies with the current directions, through grid reliability, battery storage, dual fuel or compliant gensets, before the season begins, not after a notice arrives.