Can you ever be 100% Compliant to Environmental Standards on 24×7 basis?


Compliance with environmental standards is expected to be 100% and on 24×7 basis in most countries including India. This means that if you draw a sample at any time, the concentrations of the specified pollutant must be within the set limits or standards. If not, it becomes a case of violation or non-compliance that the regulator can act upon. Even one single default becomes a case of non-compliance.

This situation is applicable for both emission/effluents as well as for ambient  environmental standards. Given this expectation, can any polluter be truly compliant? And when ambient environmental standard gets violated, how do we find the ‘culprit’?  And do we act in case of such a violation, against the regulator or against the regional agency responsible?

But I wonder how realistic it is to ask for 100% and 24×7 compliance in the first place. We all know that emissions and effluent streams are to be released after required treatment. The design of treatment and disposal systems is to be done such that compliance can be ensured. The treatment systems however receive variable quantities and sometimes unpredictable characteristics of ‘inputs’. Even given this variability (often beyond the control of the treatment system designer and operator), ‘outputs’ are expected to meet the standard, 100% of the time. Is this reasonable? And isn’t this asking for too much?

On most occasions, the regulators (e.g. Pollution Control Boards in India), use their  discretion based on how frequently the emission/effluent concentrations cross the limits? To what extent is the violation? Which are the parameters and how critical are they in positing risks or causing damage to humans and ecosystems? Occasional and marginal ‘defaulters’ are then let go with warning and fines. This can be a subjective process. Most polluters follow this first option of negotiation with the regulator and pay fines especially when the violations or noncompliances come to light.

The second option is to ‘overdesign’ the treatment and disposal systems with a ‘factor of  safety’ to handle the input variability. Most industrial effluents today are subjected to flow and load balancing and equalization tanks get added to the ‘process train’. In some cases, additional treatment processes are introduced or the treatment units are oversized. This strategy of ensuring compliance however requires more capital investments.

The third option is to reduce variability of inputs at the source itself by introducing process controls and practising effluent segregation. This option is perhaps most effective and goes well in combination with option 2 stated above.

The fourth option is to frame compliance with the standard in a statistical manner. Here, we accept the fact that 24×7 compliance on 100% basis is just not possible.

For ambient air quality in India, compliance for 98% of the time is acceptable with the annual average standard (See To calculate the annual average, the number of samples specified is 104 i.e. two samples drawn every week over 24 hours. The additional condition is that while 2% of samples may be noncompliant, violation of the standard cannot happen on more than two consecutive occasions.

I like this definition of compliance as it recognizes the fact that 24×7 and 100% compliance for ambient air quality is not possible. It then goes on to accept 98% compliance, defines the sample size and stipulates that more than two consecutive violations will not be acceptable in the noncompliance zone of 2%.

Unfortunately, what has been proposed for ambient air quality in India, the same has not been ‘translated’ to air emissions from stacks or to effluents from industries? We do not state, for example, that an effluent treatment plant at an industry will report at least 156 samples in a year (i.e. thrice a week), with samples collected on a composite basis. Out of the 156 samples, at least 95% of the samples must be compliant. Out of the 5% of the violations, non-compliant samples should not be consecutive or over two successive occasions.

Indeed, we need to bring such anomalies to the notice of the regulators and also the  judiciaries. We have to be realistic, scientific and practical. Let us not overstate the requirements of environmental compliance. While we may pursue Options 2 and 3 stated above, let us lobby with the regulators to refine environmental compliance in a statistical framework.

(You may like to read report on Environmental Compliance and Enforcement in India: Rapid Assessment  -wonder how the various statistics on compliance in this document were reported in light of thoughts expressed above. The picture used in this post is sourced from



For students – Take up a research project to review statistical or probabilistic standards – whether these are in vogue and in which countries they exist and what has been the practical experience. Cover ambient as well as emission/effluent standards. See paper “Some Historical Statistics Related to Future Standards” by Paul M. Berthouex, at as a source of inspiration..



  1. Sir

    The industrial fraternity may welcome this proposal but I am afraid because this would either make implementation of environmental statues even difficult or would have no affect at all. Theoretically, it is correct that 24×7 is not possible but implementation of a cut off like 95% in a country like India seems not possible at this stage.

    The Pollution Control Boards usually conduct surprise inspections.

    I assume that the surveillance scheme of the Pollution Control Boards result in to visits on monthly basis which mean the PCB may collect samples only 12 times a year.

    If PCB adopts 95%formula then the unit is required to comply 12*0.95 = 11.4 times which is as good as ensuring compliance 12 times.

    The extent of failure matters. If one discharges 38 mg/l BOD and if one discharges 3380 mg/ BOD vis-a-vis a standard of 30 mg/l then level of noncompliance is not same even for one isolated event.

    Or if PCB starts allowing non compliance for one in every of n number of monitoring/ year then also the problem is not solved. The value of n varies depending upon the pollution potential of the unit, sensitivity of the local people, available manpower resource at PCBs. Suppose one type of unit is inspected on quarterly basis and the unit fails in two occasions then how one should respond to the problem?

    The self monitoring data, which are shared with PCB and public by the industry often lacks reliability.

    It is the number of samples, which can be collected from one industry in the backdrop of man power strength of the PCB, that plays a determinant role in framing the compliance threshold.

    If all the industry have online monitoring systems in place and all data are directly transferred to PCB -EMIS and environment performance reports ( including the degree of failure) are generated on daily bases and actions are taken strictly basis of those reports then only introduction of such cutoff becomes feasible.

    Till today, such improvement in Indian environment monitoring system seems like a distant dream.

  2. I wonder if non-compliance zone be decided by the frequency of violations alone or coupled with ‘how much’ is being emitted in each of those violations. How can this be accounted for?

  3. Dear Dr Modak, As far as effluent treatment plants are concerned, I think the entire series of steps starting from developing a robust basis of design to effective designing, followed by operation and maintenance by competent personnel is missing in most (perhaps more than 80%) of the cases.

  4. Dear Dr. Prasad Modak,
    Talking of industries categorized as,”Most Polluting Industries”, by CPCB (e.g. alcohol distilleries, pulp & paper mills etc) I emphasize that it is possible to maintain 24/7 environmental compliance.
    The question is how. Simple logic is when the production of alcohol & paper can happen 24/7, why not the processing of the effluents emanating therefrom? continuous processes for pollution control (like anaerobic/ aerobic degradation or physical processes like RO, evaporation etc.) do exist, which can operate 24/7. Hence there is no obstacle for indeed operating 24/7. So what’s the problem?
    Only willingness is absent. Compulsion is there, but enforcement is not there, since it is easier & cheaper to entice controlling authority to look other way.
    In most of the cases, pollution control is an expenditure, which burdens the profitability of the product. Thus in case, if pollution control activity is converted into profitable or at least no profit no loss case, then there will be more willingness on part of management to comply.
    It is again indeed possible to achieve zero liquid discharge (ZLD) in case of liquid effluents & that too profitably. I am trying in that direction.
    Secondly in case of sampling of air pollution, adopting model of just 2 samples in day for verification is a joke. Everyone knows, how much air pollution exists in industrial estates, especially at night. It is free for all in these areas in night time.
    In case of air pollution, 24/7 operating processes are there to destroy the pollutants. Continuous monitoring equipped with alarm signals for excess emission is there. Who will adopt it?
    In spite of all this, if environmental compliance is made profitable, then compliance won’t be distant.
    Dr. Harshvardhan Modak

  5. Prasad

    Thanks for a very thought provoking blog for all practising professionals in the environmental field in Indiaand abroad.

    The issue of performance monitoring for wastewater treatment plants is very complicated and full of grey areas. The real challenge is to find a practical,fair & reasonable solution which is also” good in law”.

    The subject needs a lot of intellectual churning at all platforms and then deriving at a law which can be implemented, monitored and enforced with relative ease and ‘ honesty of purpose’.

    Your have contributed your bit by some useful suggestions.
    Let’s look at the proposed solutions by other professionals.

    Best regards,

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