DG Set Rules in Delhi NCR: A Simple Guide

Diesel generator sets are everywhere in Delhi NCR: in housing societies, office towers, malls, hospitals, hotels, data centres, factories and construction sites. They are also a significant source of winter air pollution, and so they are closely regulated. National emission norms under the Environment (Protection) Rules apply to every genset sold in India, with the CPCB IV+ norms for new gensets up to 800 kW. In NCR, the Commission for Air Quality Management has added directions that limit when gensets can be used and require larger ones to be converted to dual fuel or fitted with approved retrofit devices. And under the Graded Response Action Plan, as revised on 28 September 2026, actions on DG sets now begin at Stage I.

This guide explains the rules in plain words, the options for bringing a genset into compliance, what housing societies and buildings need to do, and how to handle inspections and notices. For the full service page, see DG set emission norms.

The rules at a glance

The national emission norms

Gensets sold in India must be type approved and meet emission limits set under the Environment (Protection) Rules. For new diesel gensets up to 800 kW, the CPCB IV+ norms apply, significantly reducing particulate and nitrogen oxide emissions compared with earlier norms. Each genset should carry a type approval certificate and conformity label, and must be installed with a stack of the required height and an acoustic enclosure meeting noise limits. Older gensets built to earlier norms can continue to be used where the law and local directions allow, but in NCR they face the additional CAQM requirements.

CAQM directions in NCR

The Commission for Air Quality Management has issued directions across NCR that, in broad terms, restrict the use of diesel gensets to emergencies and essential services, and require gensets above specified capacity bands that are used to be converted to dual fuel, running mainly on gas, or fitted with approved retrofit emission control devices that cut particulate emissions, within timelines the Commission has set. Smaller gensets and those in essential services have had different treatment. The directions have been revised several times, so the exact requirement for your genset depends on its capacity, use and the current direction.

Because GRAP DG set actions now begin at Stage I, restrictions that used to apply only when air quality became very poor now apply from the start of the winter season. Buildings should plan compliant backup power before October.

How to make your gensets compliant

Options compared

Housing societies and buildings

In a housing society, the maintenance agency or the residents' welfare association is usually treated as responsible for the gensets, and receives the notice. In office buildings and malls, the owner or facility manager is responsible, though tenants with their own gensets have their own duties. Hospitals and data centres, which need continuous power, may fall within essential service provisions, but must still use compliant gensets. Agreements with maintenance agencies should require compliance with CAQM directions, so that responsibilities are clear.

Inspections and notices

During winter drives, inspection teams check gensets for conformity labels, conversion or retrofit certificates, stack height, enclosures and logbooks. A genset that has been upgraded but cannot be shown to be compliant on paper is often treated as non-compliant. If you receive a notice or a sealing direction, gather the certificates and logbooks, explain the use, for example during a power failure, and apply for revocation with evidence. If a genset is not yet compliant, show the purchase order or work order for conversion and seek time. See closure notice reply.

Running hours and permitted use

CAQM directions generally allow gensets to be used for emergencies and essential services, not as a routine substitute for grid power. In practice, this means gensets in buildings and factories should run only during power failures, and the running hours should be recorded. A logbook showing date, start and stop times, load, fuel used and the reason for running is the simplest way to prove permitted use. Inspection teams in NCR often ask for it. Gensets that run for long hours every day in an area with reliable grid supply attract suspicion even if they are upgraded.

Essential services, such as hospitals, life-saving equipment, telecom towers, data centres and lifts in high-rise buildings, have been treated differently under the directions, but they must still use compliant gensets and keep records. Where a building relies on gensets because its grid connection is inadequate, applying for an enhanced connection or adding battery storage is often the long-term solution.

Costs and choices

The right route depends on numbers. Dual fuel conversion costs vary with genset size and require a piped gas connection, but reduce diesel use and emissions. Retrofit emission control devices are installed on the exhaust and require maintenance, such as periodic cleaning or regeneration. Replacement with a new CPCB IV+ genset is a larger capital cost but may suit old gensets near the end of their life. Battery storage can handle short outages and low loads without any emissions. For many buildings, a mix works best: battery storage for short outages and lighting, and an upgraded genset for longer failures.

Whatever route you choose, use suppliers whose kits or devices are approved under the CAQM directions, and insist on certificates. A cheaper, unapproved device may not be accepted at inspection, leaving you exposed.

Documents inspection teams ask for

Before the winter season