Section 21 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Section 21 is the consent section of the Air Act. In an air pollution control area, no person may establish or operate an industrial plant without the State Board's previous consent. The section sets out the application, the Board's four-month period for an order in writing, the conditions on control equipment and chimneys, variation, and what happens when the industry is transferred.
This article is current as amended up to the Jan Vishwas (Amendment of Provisions) Act, 2023 (in force for this Act from 1 April 2024). That Act substituted section 21(1), adding the proviso that lets the Central Government exempt categories of industrial plants. Later amendments and notifications should be checked. If you are preparing or defending a consent file, our compliance documentation team can help.
No person may establish or operate an industrial plant in an air pollution control area unless the State Board has given its previous consent. The application carries the prescribed fees and form. The Board must decide within four months of receipt, by order in writing with reasons recorded, granting consent on conditions and for a period, or refusing it. Grant carries duties on control equipment and chimneys. The Central Government may exempt categories of plants from sub-section (1).
Section 21(1): the prohibition and the exemption proviso
As substituted: "No person shall establish or operate any industrial plant in an air pollution control area unless the previous consent of the State Board has been obtained in pursuance of an application made by such person in accordance with the provisions of this section."
The proviso, which is the new part: "the Central Government may in consultation with the Central Pollution Control Board, by notification in the Official Gazette, exempt certain categories of industrial plants from the application of the provisions of this sub-section."
The ban is on both establishing and operating. Whether a plant falls in an exempted category depends on a Central Government notification; see the sister article on the section 21 exemption notification. The areas in which the ban applies are those declared under section 19.
Section 21(2): the application
The application "shall be accompanied by such fees as may be prescribed and shall be made in the prescribed form and shall contain the particulars of the industrial plant and such other particulars as may be prescribed". The Act itself prints no fee and no form.
Existing plants. A proviso covers a person who, immediately before an area was declared an air pollution control area, operates an industrial plant there. That person must apply within the period the Board prescribes, "being not less than three months from the date of such declaration", and if the application is made, "he shall be deemed to be operating such industrial plant with the consent of the State Board until the consent applied for has been refused". Deemed consent here lasts only until refusal.
Section 21(3): the inquiry
The State Board "may make such inquiry as it may deem fit" on the application and, in doing so, "shall follow such procedure as may be prescribed".
Section 21(4): the order within four months
"Within a period of four months after the receipt of the application for consent referred to in sub-section (1), the State Board shall, by order in writing, and for reasons to be recorded in the order, grant the consent applied for subject to such conditions and for such period as may be specified in the order, or refuse such consent."
Two provisos follow. First, the Board may cancel consent before the period expires, or refuse further consent after expiry, "if the conditions subject to which such consent has been granted are not fulfilled". Second, before cancelling or refusing further consent, "a reasonable opportunity of being heard shall be given to the person concerned".
The Act is silent on what happens if the four months pass without an order. Under section 21A the Central Government may issue guidelines on the time-bound disposal of applications; see section 21A.
Section 21(5): conditions on a consent holder
Every person granted consent must comply with these conditions:
| Clause | Condition |
|---|---|
| (i) | Control equipment of specifications the State Board approves must be installed and operated in the premises where the industry is, or is proposed to be, carried on |
| (ii) | Existing control equipment must be altered or replaced as the State Board directs |
| (iii) | The equipment in (i) or (ii) must be kept at all times in good running condition |
| (iv) | A chimney, wherever necessary, of specifications the State Board approves must be erected or re-erected |
| (v) | Such other conditions as the State Board may specify |
| (vi) | The conditions in (i), (ii) and (iv) must be complied with within the period the State Board specifies |
The first proviso says that for a plant operating in an area immediately before it was declared a control area, the period specified shall not be less than six months. The second proviso bars any alteration, replacement, erection or re-erection of control equipment or a chimney after installation, "except with the previous approval of the State Board".
Section 21(6): variation of conditions
If, "due to any technological improvement or otherwise", the State Board is of opinion that any condition needs variation, including change of control equipment in whole or in part, it shall, after giving the consent holder an opportunity of being heard, vary the condition, and the person is bound to comply with it as varied.
Section 21(7): transfer
Where a person granted consent transfers his interest in the industry to another, "such consent shall be deemed to have been granted to such other person and he shall be bound to comply with all the conditions subject to which it was granted as if the consent was granted to him originally". A buyer of a plant therefore takes the consent with its conditions.
What operating without consent leads to
Section 39D makes failure to comply with section 21 an offence, with punishments printed there; see section 39D. For how consent is applied for in practice, read our guide on how to get pollution control consent (CTE/CTO) and the sister article on the Air consent guidelines 2025.
Practical points
- Apply before you build. Section 21(1) bars establishing as well as operating.
- Diarise the four months, but do not assume deemed consent; section 21(4) does not provide it for new applications.
- Read every condition, and do not alter approved equipment without the Board's previous approval.
An example
Rajhans Steel Rolling Mills Limited is setting up a reheating furnace in an air pollution control area. The Board orders, within four months and with reasons, a grant of consent for a stated period on conditions: approved control equipment and a chimney the Board approves. After installation the company wants to change the chimney; it may do so only with the Board's previous approval.
Need help with consent documentation?
Our compliance documentation team can help you prepare the application, track the order and document compliance with each condition.
Key takeaways
- No industrial plant may be established or operated in an air pollution control area without the State Board's previous consent.
- The Board must grant or refuse by reasoned written order within four months of receiving the application.
- Consent comes with conditions on control equipment, chimneys and time limits, and may be varied after a hearing.
- The Central Government may exempt categories of plants from section 21(1), under the proviso substituted by the Jan Vishwas Act, 2023.
- Consent passes to a transferee of the industry, with its conditions.
Read next
- Section 21A: Central guidelines on consent
- Section 39D: the offence of operating without consent
- Section 25 of the Water Act: consent to establish and operate
- Pollution control CTE/CTO: the complete guide
Disclaimer: Based on the Environment (Protection) Act, 1986, the Air (Prevention and Control of Pollution) Act, 1981 and the Public Liability Insurance Act, 1991 as amended by the Jan Vishwas (Amendment of Provisions) Act, 2023 (in force for these Acts from 1 April 2024), the Water (Prevention and Control of Pollution) Act, 1974 as amended by its Amendment Act of 2024 (which applies only in the States and Union territories it names and in States that adopt it), and the National Green Tribunal Act, 2010 as amended by the Tribunals Reforms Act, 2021, as consulted on 3 October 2026. Later amendments, rules and notifications should be checked. This article is general information, not legal advice; check the official text before acting.