Pollution control boards: consent to establish, consent to operate and CPCB norms

Environmental Engineering (B.E./B.Tech) · Environmental management and compliance · free study notes for exams, placements and interviews

In short

Every industry, mine, hotel, hospital or construction project in India that discharges effluent, emits air pollutants or handles waste must obtain written permission from the State Pollution Control Board (SPCB) or Pollution Control Committee (PCC) before it is built and again before it runs — the Consent to Establish (CTE) and Consent to Operate (CTO). The legal base is the Water (Prevention and Control of Pollution) Act, 1974, the Air (Prevention and Control of Pollution) Act, 1981 and the Environment (Protection) Act, 1986, with the Central Pollution Control Board (CPCB) laying down standards, categorisation and guidance that the SPCBs enforce. Compliance decides whether a plant can legally operate, so consent management is the single most common day-to-day job of an environmental engineer in industry, in EHS consultancies and in the boards themselves. It is examined in environmental law/management papers of B.E./B.Tech, in GATE Environmental Engineering (standards and regulatory framework), and asked in almost every EHS interview.

Explained

Institutional structure and powers

CPCB (constituted 1974 under the Water Act, headquarters Delhi, under MoEFCC): lays down and publishes standards, coordinates SPCB activity, runs national monitoring networks (NAMP for air, NWMP for water), publishes category lists and technical guidelines, and acts as the board for Union Territories in some matters.
SPCBs / PCCs: grant, refuse, amend, renew or revoke consent; inspect premises; take and analyse samples; issue directions; recover fees and environmental compensation. PCCs do the same job in most Union Territories.
Statutory powers worth naming: entry and inspection, sampling with notice to the occupier, directions for closure/prohibition or stoppage of water, electricity or any service (section 33A of the Water Act, section 31A of the Air Act), and directions under section 5 of the Environment (Protection) Act, 1986 which the Central Government and its delegates use.
Air pollution control areas are declared by the State under the Air Act; within them, no industrial plant may be established or operated without consent, and specified fuels or appliances may be banned.
Appeals: against a consent order to the State Appellate Authority (section 28 Water Act, section 31 Air Act), and then to the National Green Tribunal; NGT also hears matters under the EP Act and the rules framed under it.
The Jan Vishwas (Amendment of Provisions) Act, 2023 and the Water (Prevention and Control of Pollution) Amendment Act, 2024 decriminalised many lesser offences under the Air and Water Acts, replacing imprisonment with monetary penalties imposed by an adjudicating officer; the Water amendment applies to UTs and to States that adopt it, so the position differs by State — check the State's notification. Serious offences remain criminal.

Consent to Establish and Consent to Operate

CTE (also called NOC): obtained *before* construction or installation begins. The board checks siting (distance from habitation, water bodies, eco-sensitive areas, zoning/land use), proposed products and capacity, water balance, the proposed effluent treatment plant (ETP) and air pollution control (APC) devices, solid and hazardous waste routes, and the prior Environmental Clearance where the project needs one.
CTO: obtained *before* commissioning/discharge, after the pollution control systems are actually built. It is granted on inspection and carries the binding conditions — permitted production capacity, water drawal and effluent quantity, discharge point, concentration limits for each parameter, stack height and emission limits, monitoring frequency, waste handling, and reporting.
Consolidated Consent and Authorisation (CCA): most States now issue one document covering consent under the Water Act, consent under the Air Act and authorisation under the waste rules, instead of three.
Typical application flow: online application on the SPCB portal (OCMMS/XGN, increasingly through the National Single Window System) → fee based on gross capital investment per State rules → scrutiny and queries → site inspection → committee/consent-granting authority → issue of order with conditions → display and compliance.
Renewal is applied for before expiry (commonly 30–120 days, State-specific); operating on an expired consent is operating without consent. Amendment is needed for change in product mix, capacity expansion, change in fuel, additional stack or outlet, or change of occupier.
Validity depends on category. CPCB's recommended norms are roughly 5 years (Red), 10 years (Orange) and 15 years (Green), with White exempt; several States grant longer periods or life-of-project consents for low-risk units, so quote the State's own schedule.
Other permissions sit alongside consent and are not a substitute: Environmental Clearance (EIA Notification, 2006), forest and wildlife clearances, CGWA groundwater NOC, hazardous waste authorisation, factory licence under the labour-code framework, and explosives/boiler approvals.

Categorisation: Red, Orange, Green and White

CPCB's 2016 re-categorisation replaced the old ad-hoc lists with a Pollution Index (PI) scored 0–100 from emissions to air, effluent discharge, hazardous waste generation and resource (water/energy) consumption.
Red: PI ≥ 60 — highly polluting (tanneries, distilleries, pulp and paper, dyeing, pesticides, chlor-alkali, oil refineries, cement, thermal power, pharmaceutical bulk drugs, electroplating). Not permitted in many eco-sensitive and protected areas.
Orange: PI 41–59 — moderate (automobile servicing above a size, hot-mix plants, food processing, bricks with certain kilns, large hotels, fermentation-free pharma formulation).
Green: PI 21–40 — low (assembly units, flour mills, small engineering without plating, air-cooled units).
White: PI ≤ 20 — practically non-polluting (solar and wind power, bicycle assembly, electric lamp assembly, cotton and woollen hosiery). White units need no consent to operate; an intimation to the board is enough in most States, but a CTE/siting intimation may still be required and no hazardous waste is permitted.
Category drives consent validity, inspection frequency, fee, bank guarantee, whether an online monitoring link is mandatory, and whether the unit may be sited in a given zone — hence the first question asked of any new project.
The number of entries in each list has been revised several times since 2016; use the current CPCB list rather than a remembered count.

CPCB norms and standards an engineer must know

General effluent discharge standards are in Schedule VI of the Environment (Protection) Rules, 1986, by mode of disposal — inland surface water, public sewer, land for irrigation, marine outfall. Industry-specific standards in Schedule I override the general ones.
Key inland-surface-water limits: pH 5.5–9.0; suspended solids 100 mg/L; BOD (3 days, 27 °C) 30 mg/L; COD 250 mg/L; oil and grease 10 mg/L; ammoniacal nitrogen 50 mg/L; total residual chlorine 1.0 mg/L; temperature not more than 5 °C above the receiving water; heavy metals in the 0.1–2 mg/L range by metal.
Zero Liquid Discharge (ZLD) is imposed as a consent condition on sectors such as textile dyeing, tanneries and distilleries in many States, usually with multiple-effect evaporators and reverse osmosis.
Sewage treatment plants: separate standards apply, considerably tighter than the industrial general standards (BOD and TSS of the order of 10–30 mg/L with limits on faecal coliform), and they have been varied by MoEFCC notification and NGT orders — quote the limit applicable in the State rather than a single national figure.
NAAQS, 2009 (CPCB, 12 pollutants, industrial/residential/rural areas): PM10 60 µg/m³ annual and 100 µg/m³ 24-hourly; PM2.5 40 and 60; SO₂ 50 and 80; NO₂ 40 and 80; CO 2 mg/m³ (8-h) and 4 mg/m³ (1-h); O₃ 100 µg/m³ (8-h) and 180 (1-h); NH₃ 100 annual and 400 24-h; benzene 5 annual; benzo(a)pyrene 1 ng/m³; arsenic 6 ng/m³; nickel 20 ng/m³; lead 0.5 annual and 1.0 24-h. Compliance rule: the short-term value must be met 98% of the time in a year and must not be exceeded on two consecutive monitoring days; minimum 104 observations a year (twice a week, 24-hourly).
Stack emission norms are source-specific: a general particulate limit of 150 mg/Nm³ for many small sources, 30 mg/Nm³ for cement kilns, and for coal thermal power plants the 2015 notification fixes PM 30 mg/Nm³ for new units with SO₂ and NOx limits by vintage — the compliance deadlines in that notification have been extended several times, so cite the current amendment.
Minimum stack height is prescribed by rule (for small generators and boilers by formula, e.g. height tied to SO₂ emission rate or to heat input) and appears as a consent condition.
Noise Pollution (Regulation and Control) Rules, 2000 — ambient limits in dB(A) Leq, day (6 a.m.–10 p.m.) / night: industrial 75/70, commercial 65/55, residential 55/45, silence zone 50/40.
Waste rules requiring authorisation from the SPCB: Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016; E-Waste (Management) Rules, 2022; Plastic Waste Management Rules, 2016 as amended; Battery Waste Management Rules, 2022; Bio-Medical Waste Management Rules, 2016; Construction and Demolition Waste Rules; and the Solid Waste Management Rules, 2026, which replaced the 2016 Rules from 1 April 2026. The waste streams with notified EPR regimes (plastic packaging, e-waste, batteries, waste tyres and used oil) are administered through CPCB's EPR portals.

Monitoring, reporting and enforcement

Self-monitoring at the frequency written into the consent, through an MoEFCC/NABL-recognised laboratory; records kept for inspection.
OCEMS (online continuous effluent and emission monitoring systems) with data streamed live to SPCB and CPCB servers is mandatory for the 17 categories of highly polluting industries and for common effluent treatment plants — distilleries, sugar, pulp and paper, tanneries, cement, thermal power, textile dyeing and bleaching, pharmaceuticals, chlor-alkali, fertiliser, iron and steel, oil refineries, pesticides, zinc, copper, aluminium smelters and petrochemicals.
Form V Environmental Statement must be submitted to the SPCB by 30 September each year for the financial year ending 31 March, by every unit holding consent or authorisation (Rule 14, EP Rules, 1986). Hazardous waste returns (Form 4) are due by 30 June.
Bank guarantee is taken as a consent condition against time-bound commitments (completing an ETP, installing OCEMS) and is forfeited on default.
Environmental compensation (EC) is levied by CPCB/SPCBs on polluting units using a formula based on the pollution index, number of days of violation, scale of operation, the receiving environment and location. It is compensation for damage, over and above penalty, and is distinct from a court fine.
Escalation ladder: show-cause notice → direction to improve with a time limit → bank guarantee forfeiture and EC → directions under section 33A/31A for closure and disconnection of power and water → prosecution or adjudication.
CEPI: CPCB scores industrial clusters on a Comprehensive Environmental Pollution Index (air, water, land sub-indices with health risk); clusters above the threshold are critically polluted areas, where moratoria on new Red-category consent have been imposed and lifted from time to time, and an action plan is mandated.
CREP (Charter on Corporate Responsibility for Environmental Protection, 2003) sets beyond-compliance targets for 17 sectors, generally voluntary but often written into consent conditions.

Key points

CTE – permission before establishing the unit; granted on siting, design and proposed control systems, before any construction.
CTO – permission before operating or discharging; granted after the ETP/APC systems are physically in place and inspected.
Legal base – consent under section 25/26 of the Water Act, 1974 and section 21 of the Air Act, 1981; standards and directions under the Environment (Protection) Act, 1986.
CPCB vs SPCB – CPCB sets standards and coordinates; SPCB/PCC grants consent, inspects and enforces in the State/UT.
Pollution Index – 0–100 composite score from air emissions, effluent, hazardous waste and resource use; fixes the category.
Category thresholds – Red ≥ 60, Orange 41–59, Green 21–40, White ≤ 20.
White category – no consent to operate needed, only intimation; hazardous waste not permitted.
CCA – one consolidated order combining Water consent, Air consent and waste authorisation.
Schedule VI, EP Rules 1986 – general effluent standards by disposal mode; Schedule I industry standards override them.
Inland surface water key limits – pH 5.5–9.0, BOD₃ 30 mg/L, COD 250 mg/L, TSS 100 mg/L, oil and grease 10 mg/L.
NAAQS 2009 – 12 pollutants; PM10 60/100 and PM2.5 40/60 µg/m³ (annual/24-h), with the 98th-percentile compliance rule.
Noise rules 2000 – 75/70, 65/55, 55/45, 50/40 dB(A) Leq day/night for industrial, commercial, residential, silence zones.
OCEMS – mandatory live monitoring for the 17 highly polluting categories and CETPs.
Form V – annual Environmental Statement due 30 September for the year ended 31 March.
Section 33A / 31A directions – closure and cutting of power and water; the board's sharpest tool.
Environmental compensation – damage-based levy using CPCB's formula, separate from a fine; bank guarantees are forfeited on default.
CEPI – cluster-level pollution index that has triggered moratoria on new Red-category consents in critically polluted areas.
Appeal route – State Appellate Authority, then the National Green Tribunal.

Formulas and examples

Pollution Index PI = sum of scores for air emissions, effluent discharge, hazardous waste generation and resource consumption; 0 ≤ PI ≤ 100 (dimensionless). Category: Red ≥ 60, Orange 41–59, Green 21–40, White ≤ 20.

Pollutant mass load L = Q × C ; Q = flow (m³/day), C = concentration (mg/L), L in g/day (divide by 1,000 for kg/day, since 1 m³ × 1 mg/L = 1 g).

Treatment efficiency η = (C_in − C_out) / C_in × 100 (%)

Emission rate E = C × Q_g ; C = concentration (mg/Nm³), Q_g = stack gas flow (Nm³/h), E in mg/h.

Correction of a measured stack concentration to a reference oxygen level:
C_ref = C_meas × (21 − O₂,ref) / (21 − O₂,meas) (percentages by volume, dry basis)

Addition of noise from independent sources: L_total = 10 log₁₀ ( Σ 10^Li/10 ) dB

Environmental compensation EC = PI × N × R × S × LF, where N = days of violation, R = receiving-environment factor, S = scale-of-operation factor, LF = location factor; the numerical factor tables are in CPCB's guideline and have been revised, so use the current table.

Example 1 — ETP performance and compliance. A textile unit discharges 450 m³/day to an inland stream. ETP inlet BOD 540 mg/L, outlet 26 mg/L.

η = (540 − 26)/540 × 100 = 514/540 × 100 = 95.2%
Load discharged = 450 × 26 = 11,700 g/day = 11.7 kg BOD/day
Outlet 26 mg/L < 30 mg/L → compliant on BOD for inland surface water. Load before treatment would have been 450 × 540 = 243 kg/day, i.e. the ETP removes 231.3 kg BOD/day.

Example 2 — stack result corrected for dilution. A boiler stack shows PM 168 mg/Nm³ measured at 11.5% O₂; the standard is 150 mg/Nm³ at a reference 6% O₂.

C_ref = 168 × (21 − 6)/(21 − 11.5) = 168 × 15/9.5 = 168 × 1.5789 = 265.3 mg/Nm³
265 > 150 → non-compliant. Diluting the stack with excess air lowers the measured number but not the mass emitted, which is why reference-oxygen correction is written into the consent condition.

Example 3 — NAAQS 98th-percentile check. A station records 104 valid 24-hourly PM2.5 values in a year; 5 exceed 60 µg/m³, two of them on the Monday and the Thursday of the same week, i.e. on consecutive monitoring days under twice-a-week sampling. Annual mean = 43 µg/m³.

Permitted exceedances = 2% of 104 = 2.08, i.e. 2 days. Observed 5 > 2 → fails the 24-hourly criterion.
Annual mean 43 > 40 → also fails the annual standard. The station is non-attaining for PM2.5 on both counts.

Example 4 — categorisation and consent planning. A proposed unit scores: air emissions 22, effluent 24, hazardous waste 14, resource consumption 8.

PI = 22 + 24 + 14 + 8 = 68 → PI ≥ 60 → Red category.
Consequences: CTE before construction, CTO before commissioning, CTO validity of the order of 5 years under CPCB's recommended norm (confirm the State schedule), hazardous waste authorisation, highest fee slab and inspection frequency, bank guarantee likely, and OCEMS if the sector is in the 17-category list.

Example 5 — noise at the boundary. Two blowers measured individually at the plant boundary give 78 dB(A) and 82 dB(A).

L = 10 log₁₀(10^7.8 + 10^8.2) = 10 log₁₀(6.31 × 10⁷ + 1.585 × 10⁸) = 10 log₁₀(2.216 × 10⁸) = 83.5 dB(A)
Industrial daytime limit 75 dB(A) → exceeds by 8.5 dB; acoustic enclosure or a silencer is needed. Note that the limit is an Leq over the day period, so the measured short-term level is indicative.

Feature	Consent to Establish	Consent to Operate
When	Before construction/installation	Before commissioning or discharge
Basis	Siting, capacity, proposed ETP/APC design	Actual installed systems, inspection
Typical validity	Until commissioning, commonly 5 years, extendable	5/10/15 years by category (State-specific)
Key document checked	Project report, water balance, EC if required	ETP/APC completion, trial run, test reports
Conditions	Design and construction commitments, bank guarantee	Discharge limits, monitoring, reporting, waste routes

Category	PI	Example sectors	Consent to operate
Red	≥ 60	Tannery, distillery, dyeing, pesticides, cement, thermal power	Required; shortest validity, tightest scrutiny
Orange	41–59	Food processing, hot-mix plants, large hotels, formulations	Required
Green	21–40	Assembly units, flour mills, non-plating engineering	Required; longest validity
White	≤ 20	Solar/wind power, hosiery, lamp assembly	Not required; intimation only

Where it is used

Industrial EHS departments in textile, pharma, chemical, cement, steel, sugar and power companies: maintaining CTE/CTO validity, Form V, hazardous waste returns, OCEMS uptime and inspection readiness.
Environmental consultancies and EPC firms (for example those preparing consent and clearance dossiers for NTPC, Tata Steel, UltraTech, Sun Pharma or SIDCUL/GIDC industrial estates): applications, ETP/APC design justification, compliance audits.
The boards themselves — SPCB/PCC Assistant Environmental Engineer and Scientist posts (recruited through State PSCs and board exams) and CPCB Scientist B, where this syllabus is examined directly.
Common facilities: CETPs in textile clusters (Tirupur, Panipat, Ludhiana), common hazardous waste TSDFs, and common bio-medical waste facilities — each holding its own consent and authorisation.
Real estate, hospitals and hotels: construction and demolition waste, DG set stack height and noise, STP consent for townships, bio-medical waste authorisation for hospitals.
Banks, insurers and ESG/due-diligence teams: valid consent is a standard condition precedent for project finance and for IPO disclosures; a closure direction is a reportable material event.

Interview questions

Q: What is the difference between Consent to Establish and Consent to Operate? A: CTE is granted before construction, based on siting and the proposed pollution control design; CTO is granted before commissioning or discharge, after the treatment and control systems are actually installed and inspected, and carries the operating limits.
Q: Under which Acts is consent granted? A: Section 25/26 of the Water (Prevention and Control of Pollution) Act, 1974 and section 21 of the Air (Prevention and Control of Pollution) Act, 1981; standards and directions come from the Environment (Protection) Act, 1986 and its rules.
Q: How is an industry's category decided? A: By the CPCB Pollution Index, a 0–100 score from air emissions, effluent, hazardous waste and resource consumption: Red ≥ 60, Orange 41–59, Green 21–40, White ≤ 20.
Q: Does a White-category unit need consent? A: No consent to operate; an intimation to the board suffices in most States, and it must not generate hazardous waste — but siting intimation or local permissions may still apply.
Q: Is Environmental Clearance the same as consent? A: No. EC is a central/state appraisal of a project's impacts before it starts; consent is the board's continuing operating permission with enforceable discharge limits, and both may be needed.
Q: What is the BOD limit for effluent discharged to an inland surface water? A: 30 mg/L, measured as BOD for 3 days at 27 °C, under the general standards in Schedule VI of the EP Rules, 1986; an industry-specific standard, if notified, prevails.
Q: Why are stack results corrected to a reference oxygen? A: Because adding excess air dilutes the measured concentration without reducing the mass emitted; correction to a fixed O₂ makes results comparable and prevents dilution as a compliance strategy.
Q: What happens if a unit operates on an expired consent? A: It is operating without consent — the board can issue a show-cause notice, levy environmental compensation, forfeit the bank guarantee and direct closure with disconnection of power and water under section 33A/31A; the matter may also be adjudicated or prosecuted.
Q: What is OCEMS and who must install it? A: Online continuous effluent and emission monitoring with live data to SPCB and CPCB servers, mandatory for the 17 categories of highly polluting industries and for common effluent treatment plants.
Q: What is the Form V Environmental Statement and when is it due? A: An annual self-declaration of water and raw material use, pollution generated, waste disposal and abatement measures, due to the SPCB by 30 September for the financial year ended 31 March.
Q: Difference between environmental compensation and a penalty? A: Compensation is a formula-based recovery for the damage caused and is paid to the board, applying the polluter-pays principle; a penalty or fine is punishment imposed by an adjudicating officer or court for the offence.
Q: Where would you appeal a refusal of consent? A: To the State Appellate Authority constituted under section 28 of the Water Act or section 31 of the Air Act, and thereafter to the National Green Tribunal.
Q: Your plant wants to double capacity next quarter — what regulatory steps come first? A: Apply for amendment or fresh CTE and revised CTO for the enhanced capacity, check whether the expansion triggers Environmental Clearance, re-verify the category and the ETP/APC capacity, and confirm no moratorium applies if the site is in a critically polluted cluster.

Common mistakes

Treating Environmental Clearance, factory licence and consent as interchangeable; they are separate permissions from separate authorities.
Assuming CTE covers operation. Starting production on a CTE alone, or on an expired CTO, is operating without consent.
Quoting the general Schedule VI limits for an industry that has its own notified Schedule I standard, which overrides them.
Reporting a stack concentration without correcting to the reference oxygen, or mixing mg/Nm³ (normal, dry) with mg/m³ at stack conditions.
Unit slips in load calculations — forgetting that m³/day × mg/L gives g/day, not kg/day, and confusing µg/m³ with mg/m³ in ambient air.
Reading NAAQS as an absolute never-exceed limit; the short-term values carry the 98%-of-the-time rule with the consecutive-day condition.
Reciting old lists and validity periods — categories, consent validity, fee slabs and the thermal power compliance deadlines have all been revised; cite the current CPCB list and the State's own schedule.
Forgetting that an increase in capacity, a change of fuel, a new stack or a change of occupier all require the consent to be amended before the change is made.