Explained: CAQM’s 50 mg/Nm³ PM emission limit for Delhi NCR industries, which industries it applies to, exemptions and more

The Commission for Air Quality Management in NCR and Adjoining Areas (CAQM) has proposed a tighter and uniform particulate matter (PM) emission standard for industries across Delhi-NCR. In Statutory Direction No. 98 issued on Saturday, the Commission recommended that identified industries must limit PM emissions to 50 mg/Nm³. The move follows recommendations of the Central Pollution Control Board (CPCB), based on studies by the Indian Institute of Technology Kanpur and inputs from a CPCB Technical Committee.

The Commission said the revised limit is technically achievable and necessary to curb industrial pollution. Industrial stack emissions are a major source of particulate pollution in the region and also contribute to secondary particle formation. The new standard aims to reduce emissions at source, improve air quality in industrial clusters and surrounding areas, and support broader efforts to control pollution across the National Capital Region.

What has CAQM directed?

CAQM has proposed a uniform maximum permissible limit of 50 mg/Nm³ for particulate matter emissions from identified industries across Delhi-NCR.

Why has this decision been taken?

The decision is based on CPCB recommendations and scientific studies, which concluded that a 50 mg/Nm³ limit is technically feasible and environmentally necessary to reduce industrial pollution.

Which industries will be covered?

The revised standard will apply to:

• 17 categories of highly polluting industries identified by CPCB
• Red category (medium and large) air-polluting industries
• Food and food processing units
• Textile industries operating boilers or thermic fluid heaters
• Metal industries operating furnaces

Are there any exceptions?

Yes. The new limit will not apply to industries that already have a stricter PM emission standard (below 50 mg/Nm³) under any existing consent, direction or statutory provision.

When will the new standards come into force?

• Large and medium industries: From August 1, 2026
• Remaining industries: From October 1, 2026

Why are industrial stack emissions important?

Industrial stack emissions significantly contribute to high PM levels in Delhi-NCR. They also lead to secondary particulate formation, worsening regional air quality.

What steps has CAQM taken earlier?

Since its formation, CAQM has mandated transition to cleaner fuels, prescribed emission standards for biomass- and other fuel-based boilers and furnaces, and issued approved fuel lists through statutory directions. 

Who will ensure implementation?

The governments of NCR states, the Government of NCT of Delhi, state Pollution Control Boards of Haryana, Uttar Pradesh and Rajasthan, and the Delhi Pollution Control Committee have been directed to ensure compliance within the prescribed timelines.

Will there be awareness campaigns?

Yes. Authorities have been asked to conduct intensive information, education and communication (IEC) activities to sensitise industries and other stakeholders about the revised standards.