Air pollution is a major environmental concern in Delhi-NCR, particularly during the winter months when weather conditions can trap pollutants close to the ground. To manage deteriorating air quality, authorities implement the Graded Response Action Plan (GRAP), a structured framework that introduces progressively stricter measures as pollution levels increase.

GRAP affects several aspects of daily life, including construction activities, transportation, industrial operations, and the use of diesel generator (DG) sets. For businesses, understanding these stages is essential for maintaining regulatory compliance and preparing for operational restrictions.

The plan consists of four stages, ranging from poor air quality to severe-plus conditions. Each stage introduces additional measures while retaining applicable restrictions from earlier stages.

What Is the Graded Response Action Plan (GRAP)?

The Graded Response Action Plan is an emergency response framework designed to address worsening air quality in Delhi and the National Capital Region (NCR). The Commission for Air Quality Management (CAQM) oversees its implementation and issues directions when specific pollution conditions require action.

GRAP uses air quality measurements and meteorological forecasts to determine when additional restrictions should be introduced. This approach allows authorities to take preventive action rather than waiting for pollution levels to deteriorate further.

Businesses, facility managers, construction companies, and vehicle operators should monitor official announcements to understand which measures apply to their activities.

GRAP Stage 1 to 4 and the restrictions applicable at each levelFor a detailed explanation of each stage and the changes introduced at every level, read this guide to.

GRAP Stage 1: Poor Air Quality

Stage 1 is associated with the poor air quality category, generally corresponding to an AQI of 201–300 under the standard GRAP framework.

At this stage, authorities focus on preventive measures intended to control dust, reduce avoidable emissions, and discourage activities that contribute to deteriorating air quality.

Key measures under Stage 1

Enforcing pollution-control requirements for vehicles.
Strengthening dust-control measures at construction and demolition sites.
Preventing the open burning of waste and other materials.
Improving road cleaning and dust suppression in identified areas.
Encouraging measures that reduce avoidable diesel generator use, as specified in applicable directions.

Construction and commercial activities may continue where permitted, but relevant pollution-control requirements must be followed.

Businesses should use this stage to review their environmental practices, inspect equipment, and prepare for the possibility of stricter restrictions.

GRAP Stage 2: Very Poor Air Quality

Stage 2 generally corresponds to an AQI of 301–400. It introduces additional measures to reduce emissions and manage activities that can worsen air quality.

This stage is particularly important for commercial establishments and industrial facilities that rely on diesel generators for backup electricity.

Key measures under Stage 2

Intensifying dust-control and road-cleaning measures.
Increasing public transport services where directed.
Applying additional traffic and parking management measures.
Implementing applicable restrictions on DG set operations.
Strengthening enforcement of relevant vehicle pollution requirements.

For DG set operators, the applicable CAQM directions may require approved emission-control arrangements or restrict the use of certain generators, subject to the relevant exemptions and compliance conditions.

Businesses should not assume that every generator is automatically prohibited or permitted. The applicable rules depend on the equipment, its compliance status, and the current official directions.

GRAP Stage 3: Severe Air Quality

Stage 3 generally corresponds to an AQI of 401–450. At this level, authorities introduce more restrictive measures because pollution has reached a severe category.

Construction activities, certain vehicle categories, and some industrial operations may face significant restrictions under the applicable orders.

Key measures under Stage 3

Restrictions or bans on specified construction and demolition activities, subject to applicable exemptions.
Additional restrictions on certain older vehicle categories.
Suspension of specified dust-generating industrial activities where directed.
Additional measures concerning school attendance and government office operations, as applicable.
Continued implementation of relevant Stage 1 and Stage 2 measures.

Businesses involved in construction, manufacturing, transportation, or facility management should monitor official notifications closely.

For facilities operating diesel generators, compliance with the applicable earlier-stage requirements remains important. Stage 3 should not be interpreted as replacing the restrictions already in force.

GRAP Stage 4: Severe-Plus Air Quality

Stage 4 is the highest level of the standard GRAP framework and is associated with severe-plus air quality. Under the standard AQI classification, this corresponds to an AQI above 450, although the applicable invocation decision must be checked against current CAQM directions and any operative orders.

At this level, authorities can introduce emergency measures to reduce pollution from transportation, construction, and industrial activities.

Key measures under Stage 4

Restrictions on the entry of specified trucks into Delhi, subject to applicable exemptions.
Additional restrictions on certain diesel vehicles.
More stringent restrictions on construction and demolition activities.
Directions affecting industrial units that do not meet applicable clean-fuel requirements.
Further emergency measures concerning schools, offices, and other activities, where ordered.

For businesses, Stage 4 can create operational challenges involving logistics, workforce arrangements, construction schedules, and backup power.

Facility managers should review the latest CAQM order rather than relying solely on general descriptions of Stage 4. Specific exemptions and operating conditions can vary with the applicable directions.

How GRAP Affects Diesel Generator Operations

Diesel generators are important for hospitals, offices, commercial buildings, factories, and other facilities that require uninterrupted electricity. However, their emissions can contribute to air pollution, which is why DG set operations receive particular attention under the applicable regulatory framework.

Depending on the generator category and current CAQM directions, compliance measures may include certified emission-control devices, eligible dual-fuel systems, or the use of generators meeting specified emission standards.

A Retrofit Emission Control Device (RECD) is designed to reduce particulate emissions from an existing diesel generator. Where an appropriate device is accepted under the applicable rules, it may help a facility meet certain emission-control requirements.

Before choosing an RECD, businesses should verify:

Compatibility with the generator's capacity and configuration.
Applicable certification and approval requirements.
Installation and maintenance specifications.
The specific CAQM directions governing the facility.
Documentation needed to demonstrate compliance.

An RECD should not be treated as a universal exemption from every DG set restriction. The permitted compliance options must be verified against the current rules.

Preparing Your Business for Different GRAP Stages

Businesses can reduce disruption by establishing a clear environmental compliance plan before pollution levels worsen.

1. Monitor official announcements

Follow CAQM notifications and relevant government updates to identify when a GRAP stage is introduced, modified, or revoked.

2. Review DG set compliance

Maintain an inventory of generators, including their capacity, manufacturing date, emission certification, and installed emission-control equipment.

3. Maintain proper documentation

Keep installation records, maintenance reports, certification documents, and other relevant environmental compliance records readily accessible.

4. Prepare for operational restrictions

Construction companies, logistics providers, industrial facilities, and commercial establishments should establish contingency plans for possible restrictions affecting their activities.

5. Review requirements regularly

Regulatory directions may be revised. Businesses should verify current requirements rather than relying on older articles, informal advice, or assumptions about previous GRAP seasons.

GRAP and State-Wise Pollution Control Regulations

GRAP is specifically associated with Delhi-NCR and should not be confused with the wider pollution-control framework applicable throughout India.

Businesses operating in multiple states must also consider the national emission standards and the relevant state pollution control requirements. Rules applicable to a facility in Delhi-NCR may differ from those governing a generator in Maharashtra, Karnataka, Gujarat, or Tamil Nadu.

state-wise pollution control norms for DG sets in IndiaFor additional guidance, read our related article on.

This comparison can help businesses understand why compliance planning should account for both regional emergency restrictions and the requirements applicable to individual installations.

Common Mistakes Businesses Should Avoid During GRAP Restrictions

Some businesses face avoidable problems because they begin preparing only after a stricter stage has been announced.

Common mistakes include:

Ignoring official notifications and relying only on news headlines.
Assuming all DG sets follow identical operating requirements.
Installing an emission-control device without checking its approval status.
Failing to maintain equipment and certification records.
Overlooking exemptions, deadlines, and specific conditions in official orders.
Assuming that restrictions in Delhi-NCR automatically apply in the same way to other Indian cities.

A regular compliance review helps organizations identify these issues and prepare appropriate responses.

Frequently Asked Questions

What are the four stages of GRAP?

The four stages are Stage 1 for poor air quality, Stage 2 for very poor air quality, Stage 3 for severe air quality, and Stage 4 for severe-plus air quality.

Who implements GRAP in Delhi-NCR?

The Commission for Air Quality Management (CAQM) oversees the framework and issues directions concerning the implementation, modification, and revocation of GRAP measures.

Does GRAP affect diesel generators?

Yes. Applicable CAQM directions can restrict certain DG set operations and specify permitted compliance arrangements. The exact requirements depend on the generator category and the current orders.

Is GRAP applicable throughout India?

No. GRAP is a framework for Delhi-NCR. Other regions follow applicable national environmental standards and their respective pollution-control requirements.

How can businesses prepare for Stage 3 or Stage 4?

Businesses should monitor official announcements, review their applicable environmental obligations, maintain compliance documentation, and prepare contingency plans for activities that may be restricted.

Conclusion

Understanding GRAP Stages 1 to 4 helps businesses and individuals prepare for changing air pollution conditions in Delhi-NCR. As the stages progress, restrictions can become more stringent, affecting transportation, construction, industrial activities, and diesel generator operations.

Businesses can manage these challenges by monitoring official CAQM directions, maintaining compliant equipment, reviewing emission-control requirements, and preparing operational contingency plans.

GRAP Stage 1 to 4: What Changes at Each LevelFor a complete stage-by-stage explanation, explore our detailed guide on. Regularly checking official notifications is essential because specific restrictions, exemptions, and compliance conditions may change.

Understanding GRAP Stages 1 to 4: Air Pollution Restrictions and Their Impact on Businesses

RECD FOR DG SET