The Precautionary Principle
Chapter Forty-Four
Syllabus topic 2, "Development"
Pages 177 to 180 of 595
In one line
The precautionary principle says that where serious or irreversible environmental damage is threatened, the absence of scientific certainty is not a reason to do nothing.
In the wording a student can write in an exam: the precautionary principle requires that environmental measures anticipate, prevent and attack the causes of environmental degradation; that where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation; and, in Indian law, that the onus of proof lies on the developer to show that the proposed action is environmentally benign. The first two limbs are Rio Principle 15; the third was added by the Supreme Court in the Vellore case.
The problem it answers
Environmental harm has four features that defeat an ordinary legal rule.
It is often irreversible. A species lost is lost; an aquifer contaminated may not be recoverable at any price.
The evidence arrives late. Harm is usually demonstrable only after it has occurred, which is after the point at which it could have been prevented.
The uncertainty is genuine. Not ignorance that better research would remove within the time available, but real scientific disagreement about a complex system.
The uncertainty favours whoever bears no burden. Under an ordinary rule the objector must prove harm. If harm cannot be proved until it happens, the objector always loses and the project always proceeds.
The precautionary principle is the answer to the fourth point. It moves the consequence of uncertainty from the person objecting to the person proposing.
The provision
Rio Principle 15. In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.
Broken down
Five conditions and qualifications, and an answer that lists them is much stronger than one that paraphrases the sentence.
- An approach, applied according to capabilities. The instrument deliberately says approach rather than principle, and makes application depend on what a State can do. That is a differentiated obligation, consistent with Rio Principle 7.
- A threat. Something must be threatened; the principle is not engaged by a speculative possibility with nothing behind it.
- Of serious or irreversible damage. The threshold. Minor or reversible harm does not engage it, which is what stops the principle from blocking everything.
- Lack of full scientific certainty. Not absence of evidence. There must be a scientific basis for the concern, and what is missing is conclusiveness.
- Cost-effective measures. What must not be postponed is a measure that is cost-effective, so the principle does not require expenditure without limit.
The Precautionary Principle
The Indian version
The Supreme Court in the Vellore case set out the principle "in the context of the municipal law" as meaning three things.
- Environmental measures by the State Government and the statutory authorities must anticipate, prevent and attack the causes of environmental degradation.
- Where there are threats of serious and irreversible damage, lack of scientific certainty should not be used as the reason for postponing measures to prevent environmental degradation.
- The onus of proof is on the actor or the developer to show that his action is environmentally benign.
The third limb is the Indian addition and it is the operative one. Nothing in Rio Principle 15 reverses the burden of proof, and the reversal is what converts a policy instruction into a rule a court can apply. When MU asks about the precautionary principle, saying which limb comes from the Declaration and which from the Supreme Court is the single sharpest thing a candidate can do.
Worked example
A company proposes a chemical plant two kilometres upwind of a town. The company's assessment says emissions will be within the prescribed standards. Objectors say that one of the compounds released has been associated in some studies with respiratory illness at concentrations below the standard, that the studies are contested, and that the meteorology of the valley concentrates emissions in winter.
Under an ordinary rule the objectors lose. They cannot prove harm; the standards are met; the assessment is on the record.
Under the precautionary principle the questions change. Is a threat of serious or irreversible damage made out? Respiratory illness in a population is serious; whether it is irreversible depends on the evidence, and the principle requires only one of the two. Is there a lack of full scientific certainty, as opposed to an absence of evidence? The contested studies supply the scientific basis, and what is missing is conclusiveness, so yes. Are the measures proposed cost-effective? Continuous monitoring, a taller stack, a different process or a different site each have a cost that can be assessed.
And under the Indian version the company must show that its action is environmentally benign. It cannot discharge that by pointing to compliance with a standard which the objectors say is set at the wrong level, because compliance with a standard is not the same as proof of benignity.
That is how the principle actually operates in an Indian tribunal, and it is why the third limb matters.
The criticisms
Four, and a complete answer gives them.
It can stop anything. If the threshold is read loosely, any project can be met with a contested study and an assertion of irreversibility. The qualifications in Principle 15 exist to prevent that and are frequently ignored.
The Precautionary Principle
It is asymmetric. The principle counts the risks of acting and not the risks of not acting. A power station not built has consequences too, and they fall on people without electricity.
It transfers a scientific judgment to a court. Deciding whether uncertainty is genuine and whether a threat is serious requires expertise a judge does not have, which is what the Supreme Court itself said when it pressed for tribunals with expert members.
Reversing the burden is easy to state and hard to discharge. Proving that something is environmentally benign is proving a negative, and no proponent can do it completely. In practice the burden is discharged by a sufficiently thorough assessment, which turns the principle into a procedural requirement.
What it does NOT mean
It is not a prohibition. It is a rule about what to do under uncertainty, not a rule that uncertain activities are forbidden.
It is not the preventive principle. Prevention operates where harm is known and requires it to be stopped at source. Precaution operates where harm is uncertain. Confusing the two is a common error.
It does not apply to trivial risks. The threshold is serious or irreversible damage.
Distinctions that carry marks
| Preventive principle | Precautionary principle | |
|---|---|---|
| State of knowledge | Harm is known or foreseeable | Harm is uncertain |
| What it requires | Prevent the harm at source | Do not treat uncertainty as a reason for inaction |
| Burden of proof | On the person alleging harm, as usual | In India, on the developer to show benignity |
| Source | General principle of environmental law | Rio Principle 15; Vellore |
| Indian statutory form | The consent regimes of the Water and Air Acts | Section 20 of the National Green Tribunal Act 2010 |
Quick revision
- Rio Principle 15: the precautionary approach applied according to capabilities; where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be a reason for postponing cost-effective measures.
- The Indian version has three limbs: anticipate, prevent and attack the causes; the uncertainty rule; and the onus on the developer to show the action is environmentally benign.
- The third limb is the Supreme Court's addition and is what makes the principle operative in litigation.
- Five qualifications to name: an approach, according to capabilities, a real threat, of serious or irreversible damage, where certainty rather than evidence is what is lacking, and cost-effective measures.
- Section 20 of the National Green Tribunal Act 2010 obliges the Tribunal to apply it.
- Criticisms: it can stop anything if read loosely, it is asymmetric about the risks of inaction, it hands a scientific judgment to a court, and proving benignity is proving a negative.
- Distinguish from prevention, which operates where harm is known.
The Precautionary Principle
Test yourself
1. State Rio Principle 15 and the five qualifications built into it.
That in order to protect the environment the precautionary approach shall be widely applied by States according to their capabilities, and that where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation. The qualifications are: it is an approach; applied according to capabilities; requires a threat; of serious or irreversible damage; where what is lacking is full certainty rather than evidence; and protects only cost-effective measures.
2. What are the three limbs of the Indian formulation, and which is not in Rio Principle 15?
That environmental measures must anticipate, prevent and attack the causes of environmental degradation; that lack of scientific certainty is not a reason for postponing measures against threats of serious and irreversible damage; and that the onus of proof is on the actor or developer to show that the action is environmentally benign. The third is not in Principle 15 and was added by the Supreme Court in the Vellore case.
3. Distinguish the precautionary principle from the preventive principle.
Prevention applies where harm is known or foreseeable and requires it to be stopped at source. Precaution applies where harm is uncertain and requires that the uncertainty not be treated as a reason for inaction. The difference is the state of scientific knowledge, not the seriousness of the harm.
4. Give two criticisms of the principle.
That it is asymmetric, counting the risks of acting and not the risks of not acting, so that a project's benefits to people who lack electricity or water are given no weight in the analysis. And that reversing the burden requires the proponent to prove a negative, which nobody can do completely, so that in practice the burden is discharged by a sufficiently thorough assessment and the principle collapses into a procedural requirement.
The rest of this subject
These notes are cut from the University's printed syllabus. Open the syllabus itself, or the past papers, for the same subject.