Steel and Rolling Mill Pollution: Compliance Guide

A steel unit in India, whether an integrated plant, a sponge iron kiln, an induction or arc furnace or a small re-rolling mill, needs consent to establish and operate from the State Pollution Control Board, must meet the emission standards and fuel rules that apply to it, and must handle its hazardous waste (spent pickling acid, oily sludge, used oil) under authorisation. Larger and primary units also need environmental clearance. Most enforcement against small mills is about furnace smoke, missing fume extraction, unapproved fuel and dumped slag or waste, and most of it is avoidable with records kept in order.

This guide is written mainly for owners and managers of steel units: re-rolling mills, induction furnace units, sponge iron plants, cold rolling and pickling lines. It explains what each kind of unit is expected to do, what inspectors look at, where units usually go wrong, and how to answer a notice. The last part is for residents living next to a steel cluster who want the rules enforced.

For help with a specific consent, notice or complaint, our industrial air pollution lawyers advise units on compliance and board proceedings, and act for residents in complaints and NGT applications.

The essentials

What pollution rules apply to a steel or rolling mill?

Three sets of rules apply to almost every steel unit. First, consent: section 21 of the Air Act and section 25 of the Water Act require consent to establish before you build and consent to operate before you produce, renewed before it expires. Second, standards: the emission standards that apply to your segment of the industry, set in the schedules to the Environment (Protection) Rules and written into your consent, together with the fuel your consent permits. Third, waste: the Hazardous and Other Wastes Rules 2016 for spent pickling acid, oily mill sludge, used oil and similar wastes.

Environmental clearance under the EIA Notification 2006 is a fourth layer for some units. Primary metallurgical plants such as integrated steel plants and sponge iron plants fall within it, and secondary units such as induction furnaces and rolling mills may also fall within it depending on process and capacity. Read the current schedule against your exact process before you assume you are outside it, especially before an expansion.

Category matters for paperwork. Most steel making segments, such as induction and arc furnaces and sponge iron plants, are in the red category; some rolling and finishing operations may sit in a lower category depending on the process and fuel. Check your board's current categorisation list; our guide on industry categories explains what each category means for consent validity and inspections.

Main pollution and compliance points for each kind of steel unit

The exact obligations are in your consent order. This table shows where inspectors usually focus for each segment.

Re-rolling mills: fuel and furnace smoke

Small re-rolling mills heat billets or ingots in a reheating furnace and roll them into bars, angles and sections. The rolling stands themselves make noise and scale, but the pollution problem is almost always the furnace. Older mills fired with coal or pulverised coal, or with poor burners on oil, produce black smoke that residents see and photograph every day.

The fuel question has become central. Your consent names the fuel you may use, and a switch without amending the consent is a violation even if the new fuel seems cleaner. In Delhi NCR, the Commission for Air Quality Management has restricted industries to a list of approved fuels, which has forced many coal-fired furnaces to move to piped natural gas or other approved fuels, and the use of pet coke and furnace oil has been restricted in the region. Our page on GRAP and CAQM compliance explains what applies to NCR units, including restrictions in higher GRAP stages.

Outside NCR, state boards set fuel conditions unit by unit and through state-level directions. Whatever the state, the furnace stack must meet the height and emission limits in the consent, and the board can ask for stack monitoring at any time. For the general rules on furnaces and boilers across industries, see our guide on boiler and furnace emission rules.

Induction and arc furnaces: why fume extraction decides most cases

When scrap is melted, everything on it burns off: paint, oil, rubber, plastic, zinc coating. The result is a dense brown or grey fume that rises from the crucible every time it is charged and tapped. The standard control is a hood or canopy over the furnace connected by ducting to a bag filter and a stack. Without it, the fume fills the shed and escapes through the roof, which is exactly what neighbours see.

In practice, inspectors find three recurring problems. The hood exists but is swung aside during charging because it slows the workers. The ducting is connected but the bag filter has torn bags or has been bypassed. Or the fan is switched off to save power when no one is watching. Each of these is a breach of consent conditions, and each is easy for an inspector to spot because the bag filter's dust discharge, the fan's electricity use and the shed's condition tell the story.

Scrap quality is the other control. Buying cheaper, dirtier scrap increases fume and slag. Some consents include conditions on scrap sorting and storage, and units that keep a simple record of scrap sources and pre-treatment find it easier to defend themselves when a complaint arrives. Where a unit melts coated or contaminated scrap, the bag filter dust can itself need handling as hazardous waste, so ask your consultant to check the schedules for your process.

Slag, mill scale, spent acid and used oil: what you must do with them

Steel units generate several kinds of solid and liquid waste, and they are treated differently in law. Slag and mill scale are generally not hazardous and have recognised uses: slag in road making and construction, mill scale in sintering or other recycling. What gets units into trouble is dumping them on vacant land, along drains or on the roadside, which brings complaints from neighbours and action by the board and the local body.

Spent pickling liquor from cold rolling, oily sludge from mills, used oil from hydraulic systems, zinc ash and dross from galvanising, and dust collected in some bag filters may be hazardous waste under the 2016 Rules, depending on the process and the schedules. That means the unit needs an authorisation from the State Board, must store the waste within the permitted limits, must send it only through authorised transporters to an authorised facility with a manifest for every load, and must file annual returns. Our page on hazardous waste authorisation covers the process, and the guide on manifests and transport covers the paperwork.

A pickling unit that neutralises spent acid and discharges it into a drain, or sells it informally to whoever will take it away, is taking a serious risk. If that acid turns up in a field or a nullah, the manifest trail is the first thing the board will ask for.

Sponge iron and integrated plants: clearance conditions, water and online monitoring

Sponge iron plants and integrated steel works carry a heavier compliance load than small mills. They hold environmental clearances with long lists of specific conditions on dust control at stockyards, covered conveyors, ambient monitoring stations, green belts, water use and solid waste, and they must file six-monthly compliance reports. The Environment Ministry's regional office monitors those conditions alongside the State Board's consent checks, so a plant can be in trouble with two regulators for the same lapse.

Large plants in highly polluting sectors, including iron and steel, have been directed by the CPCB and State Boards to install online continuous emission and effluent monitoring linked to the regulators. The data is watched for exceedances, and gaps in transmission are themselves treated as a compliance issue. A plant that lets its analysers drift or go offline for weeks is building a record against itself.

Water is the other recurring issue. Cooling water should be recirculated, effluent from gas cleaning, pickling or coke handling treated before any discharge, and groundwater drawn only with permission. In districts rated critically polluted in CPCB's CEPI assessments, boards have at times refused new or expanded capacity until the cluster improves, which makes an existing unit's clean record more valuable when it wants to grow.

How to get your mill compliant before the next inspection

This is the sequence we suggest to units that want to put their house in order, either before renewal or after a warning.

Our guide on consent for expansion or product change explains what to file when the mill has grown since the original consent.

Documents a steel unit should be able to show an inspector

If your mill receives a show-cause or closure notice

When Advocate B.K. Singh reviews a show-cause notice against a re-rolling mill or furnace unit, the first thing he checks is the date it was communicated and the time allowed to reply, because a missed deadline converts a fixable problem into a closure direction. The second is whether the inspection report matches what the notice alleges, because notices sometimes rely on observations that the report itself does not support.

A good reply admits what is true, shows what has been fixed with dated photographs and documents, explains anything the inspector misunderstood, and offers a hearing. It does not argue with every line. If the board has already issued a direction under section 31A of the Air Act, including closure or disconnection of power, an appeal lies to the NGT within 30 days of communication, extendable by up to 60 days for sufficient cause. Our pages on closure notice replies and environmental compensation demands explain how we approach each.

Restoration of power after closure normally depends on showing compliance to the board, often with an inspection and sometimes a bank guarantee. Units that have kept the records listed above get through this much faster.

Ten-minute self-check for a steel unit

Living next to a steel unit: how to complain

If you live beside a rolling mill or furnace unit, write to the State Board's regional office with the unit's name, the times when smoke or fume is worst, dated photos and videos of the stack or shed roof, and any dumped slag or waste. Ask for an unannounced inspection at those times, and for a copy of the unit's consent through RTI. In NCR, burning coal or other unapproved fuel can also be reported to CAQM's inspection teams. Our guide on complaining about factory smoke sets out the full process.

Rolling mills are also loud, with shears and stands running round the clock. Industrial noise has its own limits under the Noise Rules, 75 dB(A) by day and 70 at night in industrial areas and much lower in residential areas, and our guide on factory machinery noise explains how to use them. Where a steel cluster is causing serious, continuing harm and the board has not acted, the NGT can order a joint committee inspection and directions.

Where steel units usually go wrong

The commonest mistake is growth without paperwork: a second furnace added, capacity doubled or a fuel changed, with the consent still describing the plant as it was five years ago. On inspection, everything beyond the consent is treated as unauthorised. The second is treating pollution control equipment as something to switch on for inspections; electricity records and the state of the bag filter give that away quickly.

The third is informal waste disposal, especially of spent acid and oily sludge, which carries the highest legal risk because it can contaminate land and groundwater. The fourth is ignoring a notice or replying late. Boards are generally willing to give a unit that shows genuine compliance a chance; they have little patience with silence. A refusal of consent or a condition you disagree with can be taken first to the state appellate authority; our page on appealing a pollution board order explains the route.

Related guides

Cement and steel plants are often neighbours in the same districts; our guide on cement plant dust and stack emissions covers the cement side. For units in sectors that also handle solvents and chemical waste, see pharmaceutical unit pollution rules.