Industrial Odour and Bad Smell Complaints: What the Law Says

Yes, a persistent bad smell from a factory can be unlawful in India, even though there is no single numerical 'smell limit' you can test it against. Odour comes from gases and vapours, and those are air pollutants under the Air (Prevention and Control of Pollution) Act 1981. A unit's consent order can and often does require odour control. A smell that makes a locality's air unfit is also a public nuisance the SDM can order removed. The practical difficulty is proof, because a smell leaves no photograph.

Smell complaints are among the hardest pollution complaints to win and among the most common. The smell comes and goes with the wind, the factory says it smells nothing, and the inspector arrives on a still afternoon when the air is clear. This guide explains what the law actually says about odour, which authority deals with which kind of smell, and how residents build a record that holds up.

If you can also see smoke from a chimney, read our guide on how to complain about factory smoke alongside this one. For the overall picture of emissions, odour and dust from industry, see our page on factory air pollution and odour complaints.

The essentials

Is a bad smell from a factory illegal in India?

A persistent, strong smell from a factory is very often unlawful, but you have to show it through the right door. The Air Act defines an air pollutant as any solid, liquid or gaseous substance in the atmosphere in a concentration that may be injurious to people, other living things, plants, property or the environment. The compounds behind industrial smells, such as hydrogen sulphide, ammonia, amines, mercaptans and solvent vapours, are gaseous substances. When they reach your home in a concentration that gives people headaches and nausea, that is air pollution in the legal sense.

The Air Act then requires the unit to have the State Board's consent and to keep its emissions within standards. Consent orders for smell-prone industries, such as rendering, tanning, fish processing, distilleries and some chemical and pharmaceutical units, commonly include conditions on enclosing processes, covering raw material, treating vent gases and handling sludge. Breaking those conditions is a violation the board can act on.

Separately, a smell that makes life in a locality miserable is a classic public nuisance. The SDM or DM can deal with it under section 152 of the Bharatiya Nagarik Suraksha Sanhita 2023, and the old IPC offence of making the atmosphere noxious to health has been carried into the Bharatiya Nyaya Sanhita 2023. Neighbours directly affected can also go to a civil court for an injunction against a private nuisance, though that route is slow.

Is there a legal limit for odour?

Not a general one. India does not have a single ambient 'odour standard' that applies to every industry, and you cannot get a reading at your gate and compare it with a national smell limit. The National Ambient Air Quality Standards cover pollutants such as particulate matter, sulphur dioxide, nitrogen dioxide, ozone and ammonia, but they are designed for general air quality, not for an intermittent smell from one unit.

What exists is a patchwork. The schedules to the Environment (Protection) Rules 1986 set emission standards for particular industries, and some of these cover odour-causing gases from specific processes. CPCB has published technical guidance on odour control. And each unit's consent order can impose specific odour conditions. In practice the consent order is the most useful document: get it by RTI and read what it requires the unit to do about smell.

This matters for your complaint. A request that says 'the smell exceeds the legal limit' gives the unit an easy reply. A complaint that says 'the unit is not keeping its raw material covered and its scrubber is not running, contrary to its consent conditions, and the smell reaches our homes every evening' gives the board something it can check and enforce.

Common industrial smells and where they usually come from

Describing the smell accurately helps the inspector know what to look for. These are typical associations, not a laboratory diagnosis.

Who do I complain to about a factory smell?

The State Pollution Control Board, or the DPCC in Delhi, is the main authority for a smell from an industrial unit. It can check the unit's consent conditions, monitor the air, issue a show-cause notice and, if needed, give directions under section 31A of the Air Act to fix the problem or close. Complain at the regional office in writing and keep the diary number.

The SDM is the right second door where the smell affects a whole locality, a school or a hospital. A public nuisance application under section 152 BNSS does not depend on any pollution standard; the question is whether the trade is injurious to the health or comfort of the community. Where the smell comes from a municipal facility, such as a sewage treatment plant, a compost plant or a dumping ground, the municipal body is a necessary party; see our guide on a landfill or dumping ground near your home.

Some smells come from water, not air. A nala carrying factory effluent, a stagnant pond of untreated waste water or an ETP that is overloaded will smell, and the real violation is under the Water Act. In those cases, frame the complaint around the discharge and see our guides on tannery pollution and distillery and sugar mill effluent.

How do I prove a smell?

With numbers of people, consistency and timing. A single household saying the air stinks is easy to dismiss as a neighbour's grudge. Ten households, in different lanes, each recording the same smell at the same hours, with the wind blowing from the factory each time, is a pattern no inspector can ignore. That is what an odour diary does.

In odour matters Advocate B.K. Singh has taken up for residents, the evidence that moved the inspecting team was rarely a single dramatic video. It was a shared diary, kept by several families for three or four weeks, showing that the smell came at the same times the unit was loading raw material or cleaning its tanks. Once the board saw the pattern, it inspected at those hours and found the cause.

Back the diary with what you can document. Note symptoms such as headaches, nausea, vomiting or sore eyes, and keep the doctors' slips. Photograph conditions that cause smell, such as uncovered carcass trucks, open sludge heaps or overflowing drains, from a public place. If a school or anganwadi has had to shut windows or move children, a letter from the head teacher is worth more than an adjective in your complaint.

What to record in an odour diary

Give each participating household a simple sheet and collect them every week. Keep entries short and honest; a diary that records every single hour as 'unbearable' looks invented.

How to make an industrial odour complaint

What the board can make a smelly unit do

Odour is usually fixable, and the board's directions tend to be practical. Common requirements are enclosing the smelly part of the process and keeping it under negative pressure, so air is drawn in rather than leaking out; passing the extracted air through a scrubber or biofilter; covering and limiting raw material storage; processing perishable material quickly; cleaning tanks and drains on a schedule; and treating or removing sludge instead of leaving it in the open. Raising the vent stack can help disperse what remains.

If the unit does not comply within the time given, the board can direct closure or stoppage of electricity and water under section 31A of the Air Act and levy environmental compensation. Units in the more polluting categories may also face a review of their consent on renewal. Pharmaceutical and chemical units, where solvent smells are common, face specific obligations; see our guide on pharmaceutical unit solvent emissions and waste rules.

A unit that genuinely meets its standards but still sends a smell over a colony is in a grey area under the Air Act. Nuisance law fills that gap: the SDM can still act, and the NGT, applying the precautionary principle under section 20 of the NGT Act, can direct additional measures where the evidence shows real harm to residents.

Can a factory be closed or made to pay only because of smell?

It can, but closure for smell alone is the exception, not the rule. The usual sequence is inspection, a notice, directions with deadlines, and closure only if the unit fails to comply or the smell is causing serious harm. Boards and the NGT prefer an order that fixes the problem over one that shuts a unit employing local people, unless the unit has no consent or is in the wrong place altogether.

Compensation is possible too. Environmental compensation is levied by the board or ordered by the NGT on the polluter pays principle and goes towards environmental restoration. Separately, people who have suffered, for example through illness requiring treatment or loss of business, can claim relief under section 15 of the NGT Act within five years. Such claims need medical and financial records linking the harm to the unit; see our page on compensation for pollution damage.

Your unit has received an odour complaint: what to do

Take it seriously early, because odour complaints rarely fade on their own and they tend to grow into group complaints, SDM proceedings and NGT applications. Start by walking the site at the hours residents are complaining about. Smell problems often come from a single weak point: an uncovered raw material bay, a sludge heap, a scrubber pump that trips at night, a drain that backs up when production peaks.

Then read your own consent order. If it carries odour conditions, document how you meet each one: photographs of enclosed storage, scrubber running logs and electricity readings, sludge disposal records, cleaning schedules. Reply to the board's notice with those records and a short, dated plan for anything that needs fixing. A reply that offers a biofilter or an enclosure within a stated period usually lands better than a denial that the unit smells at all.

Talk to the neighbours too, ideally through the RWA or panchayat. Sharing your timetable for raw material deliveries or tank cleaning, and changing it where possible, can lower the temperature quickly. If the board issues a direction under section 31A that you believe is wrong, remember that an appeal to the NGT runs only 30 days from communication; see our page on appealing a pollution board order.

Before you file an odour complaint

When an odour complaint is unlikely to succeed

Some smells are temporary and some are not from the unit you suspect. A smell that appears for a few days during monsoon flooding of a drain, or once a year during a plant shutdown and cleaning, rarely justifies more than a complaint and a conversation. Before going further, make sure you have the right source; an industrial area often has several candidates, plus sewage and garbage.

Be wary, too, of farm smells. Seasonal manure spreading or a cattle shed in a village is a different legal question from an industrial unit, and complaints against ordinary agricultural activity are hard to sustain. Poultry farms and large dairies sit in between, and the position depends on state rules. If in doubt, ask before you file; a weak case at the NGT is worse than a good complaint at the board.

Related guides

Odour often travels with other problems. For smells tied to slaughter and meat waste, see slaughterhouse pollution rules and complaints. For a smelly sewage plant in your own society, read STPs operating without consent. And for help drafting the first complaint, see our page on pollution complaints.