Purpose of the Act

The Air (Prevention and Control of Pollution) Act, 1981, is a significant environmental legislation in India, enacted specifically to address the issue of air quality management. It was passed by the Indian Parliament in response to decisions made at the United Nations Conference on the Human Environment held in Stockholm in 1972, which highlighted the need for countries to preserve the quality of air.

Prior to this Act, the Water (Prevention and Control of Pollution) Act, 1974, had already established the Central Pollution Control Board (CPCB) and State Pollution Control Boards (SPCBs). The Air Act extended the mandate and functions of these boards to include the prevention and control of air pollution.

Prevention, control and abatement of air pollution

The main purpose of the Air Act, 1981, is to provide a legal framework for the prevention, control, and abatement of air pollution throughout India. These three aspects cover a comprehensive approach to managing air quality:

• Prevention: This involves taking measures to stop air pollution from occurring in the first place. This is achieved through regulating the sitting of industries (especially in 'air pollution control areas'), requiring polluting units to install and operate air pollution control devices (APCDs) before starting operations, and setting standards that must be met.
• Control: This refers to managing and reducing pollution from existing sources. The Act provides powers to the Pollution Control Boards to inspect facilities, monitor emissions, issue directions to modify operations or install/upgrade pollution control equipment, and ensure that units comply with emission standards.
• Abatement: This involves reducing the intensity or severity of existing pollution and taking steps to bring down pollution levels in areas where they exceed desirable standards. This could include actions like restricting certain activities during periods of high pollution or implementing programs for improving ambient air quality.

The Act defines "air pollutant" very broadly in Section 2(b) as "any solid, liquid or gaseous substance (including noise) present in the atmosphere in such concentration as may be or tend to be injurious to human beings or other living creatures or plants or property or environment". This comprehensive definition ensures that various forms of atmospheric contamination, including noise, fall under the purview of the Act, allowing for their regulation.

The Act empowers the CPCB and SPCBs to carry out functions necessary for achieving these objectives, such as setting standards, conducting research, collecting and disseminating information, and implementing pollution control programs.

Extent of Applicability

The Air (Prevention and Control of Pollution) Act, 1981, has a broad geographical and functional applicability.

Geographically, the Act applies to the whole of India. This is specified in Section 1(2) of the Act. Unlike the Water Act, which initially applied only to states that adopted it, the Air Act was framed to have nationwide applicability from its commencement, although states could adopt its provisions at different times initially.

Functionally, the Act's regulatory provisions, particularly concerning controls on industrial operations and emissions, are most directly enforced within areas declared as "air pollution control areas" by the State Governments. Section 19(1) of the Act empowers the State Government, after consultation with the State Pollution Control Board, to declare any area or areas within the state as an "air pollution control area" by notification in the Official Gazette. They can also alter or extend such areas (Section 19(2)).

Within these declared air pollution control areas, the following restrictions and requirements apply (Section 21, 22):

• Consent Requirement: No person shall establish or operate any industrial plant in such an area without the previous consent of the State Pollution Control Board. This is the Consent mechanism (Consent to Establish and Consent to Operate) for air emissions.
• Restrictions on Fuel Usage: The State Government can prohibit the use of any fuel other than an approved fuel in such areas or within specified industrial plants.
• Restrictions on Appliances: The State Government can prohibit the use of any appliance other than an approved appliance in such areas.
• Regulation of Emissions: The Act and the rules/standards framed under it regulate the emission of air pollutants from chimneys, stacks, and other sources within these areas.

While the strict regulatory controls like the consent mechanism apply mainly within the notified air pollution control areas, the general provisions related to standards (like NAAQS) and the powers of the Boards apply nationwide. However, the designation of air pollution control areas is a key tool for focusing regulatory efforts on regions with significant industrial activity or population density contributing to air pollution.

The Act covers emissions from various sources, including industrial plants, vehicles, and other activities contributing to air pollution, and provides the CPCB and SPCBs with the necessary powers to monitor, regulate, and enforce compliance.

Ambient Air Quality Standards

To effectively manage air pollution, it is essential to define the desired quality of the air we breathe. This is achieved through the establishment of Ambient Air Quality Standards. These standards specify the maximum permissible concentrations of various air pollutants in the ambient atmosphere, i.e., the air outside buildings that is accessible to the general public.

National Ambient Air Quality Standards (NAAQS)

In India, the National Ambient Air Quality Standards (NAAQS) are set by the Central Pollution Control Board (CPCB) under the authority derived from the Air (Prevention and Control of Pollution) Act, 1981, and the Environment (Protection) Act, 1986. The NAAQS define the acceptable limits for various pollutants to protect public health and the environment.

The most recent revision of the NAAQS was notified on November 18, 2009, replacing the previous standards from 1994. The 2009 NAAQS specifies limits for twelve key air pollutants across different averaging periods (e.g., 24-hourly, annual).

The 12 pollutants covered under the 2009 NAAQS are:

• Sulphur Dioxide ($SO_2$)
• Nitrogen Dioxide ($NO_2$)
• Particulate Matter ($PM_{10}$)
• Particulate Matter ($PM_{2.5}$)
• Ozone ($O_3$)
• Carbon Monoxide (CO)
• Ammonia ($NH_3$)
• Lead (Pb)
• Nickel (Ni)
• Arsenic (As)
• Benzene ($C_6H_6$)
• Benzo(a)Pyrene ($BaP$) - particulate phase

Examples of typical standards from the 2009 NAAQS (note that these vary by averaging period):

• $PM_{10}$: $100 \, \mu g/m^3$ (24-hourly), $60 \, \mu g/m^3$ (Annual)
• $PM_{2.5}$: $60 \, \mu g/m^3$ (24-hourly), $40 \, \mu g/m^3$ (Annual)
• $SO_2$: $80 \, \mu g/m^3$ (24-hourly), $20 \, \mu g/m^3$ (Annual)
• $NO_2$: $80 \, \mu g/m^3$ (24-hourly), $40 \, \mu g/m^3$ (Annual)
• CO: $2 \, mg/m^3$ ($2000 \, \mu g/m^3$) (8-hourly), $4 \, mg/m^3$ ($4000 \, \mu g/m^3$) (1-hourly)

These standards are uniform nationwide and are used by the CPCB and State Pollution Control Boards (SPCBs) to monitor ambient air quality and assess the pollution status of different areas. Monitoring networks are established and operated to collect data and compare it against these standards. Exceedances of NAAQS trigger the need for remedial actions and the development of air quality management plans.

Emission Standards

While ambient air quality standards define the target air quality, Emission Standards specify the maximum permissible quantity or concentration of pollutants that can be released from specific sources (e.g., industrial stacks, vehicle exhausts, generator sets). These are source-specific standards designed to control pollution at its point of origin.

Standards for industrial sources and vehicles

Emission standards in India are primarily notified under the Environment (Protection) Rules, 1986, which are framed under the Environment (Protection) Act, 1986. The Central Pollution Control Board (CPCB) provides technical recommendations based on feasibility and available technology, and the Ministry of Environment, Forest and Climate Change (MoEF&CC) notifies these standards.

Standards for Industrial Sources:

The standards for industrial emissions are often referred to as Minimal National Standards (MINAS). These are specific to different categories of industries and processes. They prescribe maximum permissible concentration limits for various pollutants in the emissions exiting from stacks or outlets. For instance, there are specific standards for emissions from thermal power plants, cement plants, fertiliser units, textile industries, etc. These standards take into account the nature of raw materials, the process used, and the potential pollutants generated by that particular industry type. Industries are required to install and properly operate Air Pollution Control Devices (APCDs) like scrubbers, electrostatic precipitators, bag filters, etc., to meet these standards. Compliance is verified through stack monitoring and inspections by SPCBs.

Standards for Vehicular Emissions:

Vehicular emission standards in India are known as Bharat Stage (BS) norms (currently BS VI). These norms are equivalent to European Emission Standards (Euro norms) and are notified by the MoEF&CC under the Environment (Protection) Rules, 1986, but enforced by the Ministry of Road Transport and Highways under the Motor Vehicles Act, 1988. BS norms set limits for pollutants like Carbon Monoxide (CO), Hydrocarbons (HC), Nitrogen Oxides ($NO_x$), and Particulate Matter (PM) from both petrol and diesel vehicles. The standards have become progressively stricter with each stage (BS IV, BS VI) requiring significant technological advancements in vehicle engines and exhaust treatment systems (like catalytic converters and diesel particulate filters). Compliance is checked during type approval of new vehicles and periodically for in-use vehicles through the 'Pollution Under Control' (PUC) certificate system.

In addition to these, there are also emission/noise standards for generator sets and other specific sources, notified under the same framework.

Emission standards are a direct regulatory tool for controlling pollution at the source, complementing the ambient standards which define the desired air quality levels in the environment.

Control of Air Pollution

The Air (Prevention and Control of Pollution) Act, 1981, and the rules framed thereunder provide the legal mechanisms and powers to the regulatory authorities (CPCB and SPCBs) to prevent and control air pollution. These mechanisms include prohibiting unauthorised discharges and implementing a mandatory consent system for polluting units.

Prohibition of discharge of air pollutants in atmosphere

The Air Act, 1981, makes it an offence to cause or permit the discharge of air pollutants that exceed the prescribed standards. While Section 21 mandates consent for operation, Section 22 directly addresses the act of causing pollution. Section 22 states that:

"No person operating any industrial plant, in any air pollution control area, shall discharge or cause or permit to be discharged the emission of any air pollutant in excess of the standards laid down by the State Board under clause (d) of sub-section (1) of section 17."

This section effectively prohibits the discharge of air pollutants from industrial sources that violate the emission standards set by the SPCB (which are based on national standards). Although phrased as exceeding standards rather than a blanket prohibition on any discharge, when read with the consent mechanism (Section 21), it implies that any discharge of air pollutants, especially from scheduled industrial processes within air pollution control areas, is permissible only if it is within the limits specified in the standards and is covered by a valid Consent to Operate from the SPCB.

Violations of Section 22 are punishable under Section 38 of the Act, which can lead to imprisonment or fines. This provision places the onus on the operator of the industrial plant to ensure that their emissions comply with the legal requirements.

Consent to operate for industries**

The primary preventive and control mechanism for air pollution from industrial sources is the mandatory Consent mechanism, similar to that under the Water Act. This is governed by Section 21 of the Air Act, 1981.

Section 21 requires that no person shall, without the previous consent of the State Board, establish or operate any industrial plant in an air pollution control area. This translates into a two-stage consent process for industries (and certain other specified units) located in areas declared as 'air pollution control areas' by the State Government:

• Consent to Establish (CTE): Required before the construction or setting up of the industrial plant begins. The SPCB reviews the proposed location, technology, and planned pollution control measures (APCDs) to ensure they are adequate to meet the required standards.
• Consent to Operate (CTO): Required before the industrial plant commences production and starts emitting air pollutants. The SPCB verifies that the installed APCDs are functional and that the unit is capable of complying with the prescribed emission standards and other conditions.

When granting Consent (CTE or CTO), the SPCB can impose various conditions under Section 21(5). These conditions are designed to ensure compliance with the Act and relevant standards and may include:

• The emission standards to be complied with for specific pollutants.
• Specifications for the design and operation of air pollution control equipment (APCDs).
• Requirements for stack height.
• Protocols for monitoring emissions (frequency, location, parameters) and ambient air quality.
• Requirements for installing continuous emission monitoring systems (CEMS).
• Submission of monitoring data and compliance reports.

Consent is typically granted for a fixed period and requires periodic renewal. Operating an industrial plant in an air pollution control area without a valid Consent to Operate, or failing to comply with the conditions specified in the consent order, is a punishable offence under Section 37 of the Act, leading to potential imprisonment and fines. The consent mechanism is thus the critical legal tool used by SPCBs to permit and regulate emissions from industries and enforce air quality standards.

Functions related to Air Pollution

The Central Pollution Control Board (CPCB) and the State Pollution Control Boards (SPCBs) (or Pollution Control Committees) are the primary regulatory bodies in India responsible for the implementation and enforcement of the Air (Prevention and Control of Pollution) Act, 1981. Their powers and functions related to air pollution are extensive and crucial for managing air quality across the country.

Advising government on air pollution matters

A key function of both the CPCB and SPCBs is to serve as expert advisors to the respective governments on matters pertaining to air pollution. This ensures that policy decisions and programs are informed by technical expertise and practical experience in pollution control.

• CPCB (Central Level): Section 16(1)(c) of the Air Act, 1981, mandates the CPCB to advise the Central Government on any matter concerning the prevention, control, or abatement of air pollution. The CPCB provides recommendations on national air quality policies, standards for industries and vehicles, strategies for managing air pollution from various sectors, and amendments to the Air Act or related rules.
• SPCBs (State Level): Similarly, Section 17(1)(d) of the Air Act, 1981, empowers SPCBs to advise the State Government on matters concerning air pollution within the state. This includes advising on the declaration or alteration of 'air pollution control areas', identifying sources of pollution, suggesting state-specific control measures, and providing input on the environmental suitability of sites for industrial development from an air quality perspective.

This advisory role is vital for translating scientific understanding and regulatory experience into effective governance and planning for air quality management.

Setting emission standards

While the power to notify legally binding emission standards primarily lies with the Central Government (MoEF&CC) under the Environment (Protection) Act, 1986, the CPCB plays a crucial technical role in their development, and the SPCBs implement and sometimes set specific conditions based on these standards.

• CPCB (Central Level): Under Section 16(2)(h) of the Air Act, 1981, the CPCB can lay down standards for the quality of air (National Ambient Air Quality Standards - NAAQS). Although not directly 'emission' standards, NAAQS inform the required stringency of source-specific emission limits. More significantly, the CPCB undertakes detailed studies and provides technical recommendations to the MoEF&CC for setting industry-specific emission standards (MINAS) under the Environment (Protection) Rules, 1986.
• SPCBs (State Level): SPCBs are empowered under Section 17(1)(g) of the Air Act to inspect air pollution control areas, industrial plants, and other premises and to take samples of air or emission from any chimney, flue, or other outlet. While SPCBs enforce the national emission standards notified by MoEF&CC, when granting Consent to Operate, they specify the exact permissible emission limits for individual units as conditions of the consent. These conditions must be in line with the notified standards but can sometimes be made more stringent based on local conditions or the assimilative capacity of the environment.

This dual role ensures that national standards are developed based on technical expertise and then enforced and tailored to specific units at the state level.

Monitoring air quality

Monitoring is a core function that provides data on pollution levels, helps identify problem areas, assesses the effectiveness of control measures, and checks compliance with standards.

• CPCB (Central Level): Section 16(1)(j) of the Air Act, 1981, directs the CPCB to collect and disseminate information regarding air pollution. The CPCB designs and coordinates national ambient air quality monitoring programs, such as the National Air Monitoring Programme (NAMP) and the National Ambient Air Quality Monitoring Programme (NAAQMP, after 2009). It collaborates with SPCBs and other agencies to set up monitoring stations, collect data on NAAQS parameters, analyse trends, and publish reports on the status of air quality in various cities and regions across India.
• SPCBs (State Level): SPCBs are responsible for monitoring ambient air quality within their states, often as part of the national programs coordinated by CPCB (Section 17(1)(h) of the Air Act). They operate air quality monitoring stations and collect data to check compliance with NAAQS. Furthermore, SPCBs are mandated to conduct source monitoring, i.e., monitoring emissions from industrial stacks and outlets (Section 17(1)(g)). Industries are required to provide sampling facilities, and in many cases, install Continuous Emission Monitoring Systems (CEMS), the data from which is also monitored by SPCBs.

Through these monitoring activities, the Boards keep track of pollution levels and gather evidence for enforcement actions.

Issuing directions and penalties**

The Boards are vested with significant legal powers to enforce the provisions of the Air Act and take action against non-compliant entities. These powers include issuing binding directions and initiating legal proceedings leading to penalties.

• Issuing Directions: One of the most potent powers is granted under Section 31A of the Air Act, 1981 (introduced via amendment). This section empowers both the CPCB and SPCBs to issue any directions in writing to any person, officer, or authority. These directions are legally binding. The scope of these directions is very broad and can include orders for:
  • The closure, prohibition, or regulation of any industry, operation, or process.
  • Stopping or regulating the supply of electricity, water, or any other service.
  • Directing specific actions for the prevention, control, or abatement of air pollution.
  This power allows the Boards to take immediate and decisive action against sources causing significant pollution or violating legal requirements.
• Imposing Penalties and Prosecution: The Air Act specifies penalties for various offences:
  • Section 37: Provides for imprisonment for a term which shall not be less than one year and six months but which may extend to six years and with fine for failure to comply with Section 21 (operating without consent) or Section 22 (exceeding emission standards). In case of continued contravention, an additional fine of up to ₹5,000 per day can be imposed.
  • Section 38: Lists various other offences (like obstructing Board personnel, providing false information, failure to furnish information) punishable with imprisonment up to three months or fine up to ₹10,000 or both.
  • Section 39: Deals with enhanced penalty for continued contravention after conviction under Section 37. If the failure continues beyond one year, the punishment can extend to imprisonment for a term up to seven years.
  The Boards (or any officer authorised by them) can initiate prosecution against individuals or companies in the courts for these offences. They can also seek injunctions from courts under Section 33 to restrain persons from causing pollution.

These powers of issuing directions and imposing penalties are essential tools that the Boards use to enforce compliance with air pollution control laws and deter violations.