6.2 Basis for Evaluation of EIA Reports
It is therefore necessary to adopt appropriate evaluation criteria for assessment of EIA reports. Uniform evaluation criteria assume greater importance because of the diverse background of the members of the expert committee. In absence of an evaluation criteria decision of the committee may be influenced by the interest group lobbying. Moreover all applications for environmental clearance submitted to the ministry are subjected to initial scrutiny by the officials of the ministry, who also carry out a preliminary assessment. However, the basis for such initial assessments is not clear. This leaves ample scope for inconsistency between the assessments done by the IAA officials and that by the expert committee.

The research has all-through viewed EIA as a decision making tool under the focus shift of human development paradigm towards environmental sustainability. The underlying premises of environmental sustainability include the following (Khanna 1996):
1. Symbiotic relationship between consumer (human race) and producer (natural systems).
2. Compatibility between ecology and economics.

In Chapter-3 the linkages between environmental sustainability and the carrying capacity of the ecosystem have been brought to light. Only an explicit incorporation of carrying capacity concept into EIA can ensure environmental sustainability of projects. However, environmental sustainability being the buzzword of only the nineties, one should not expect from the existing EMPs any link to the regional carrying capacity. It would nevertheless be logical to expect a reasonable consideration of the impact of the proposed projects on the biophysical environment. As has repeatedly been emphasised minor focus change of the existing EIA studies can be a big leap towards environmental sustainability.

Strictly speaking EIA evaluation criteria do not intend to evaluate the methodology in use. Rather the focus is often on the evaluation of the EIA process and its effectiveness in fulfilling the stated objectives of carrying out the EIA study.

Leu et al. (1996a) developed a seven stage procedure for studying the effectiveness of EIA systems in Taiwan. They grouped the domestic and international factors affecting the EIA system into the following seven categories:
1. Environmental policies;
2. Administrative framework;
3. EIA procedure;
4. Role of actors involved;
5. EIA compliance monitoring and enforcement;
6. EIA implementation imprecates; and,
7. Availability of resources.

The above factors together with the following three additional factors make an effective EIA system (Leu et al. 1996b):
1. Status of EIA;
2. Implementation of strategic environmental assessment (SEA);
3. International interactions.

According to Wood (1995) EIA evaluation criteria are, in effect, shorthand versions of principles of EIA and if carefully articulated, these may have considerable advantages in terms of brevity and clarity. Largely following Wood (1995) the author proposes the following basic principles to be followed while reviewing an EIA system.

1. Adherence to local, regional, national and global sustainability criteria.
2. Ensuring that all types of projects having significant implications for environmental sustainability are required to carry out EIA studies.
3. Provision of means for identifying best options. This cannot be achieved without a critical examination of the project objectives and the feasible alternatives.
4. An appropriate institutional arrangement. The laws enacted must be specific, mandatory and enforceable.
5. A transparent decision making process.
6. Stipulations, if any, in the environmental clearance should be backed by an effective compliance monitoring.
7. The EIA process design should be oriented towards efficient implementation.

Wood (1993, 1995) suggested 14 criteria for evaluating EIA systems. Evaluation of methodological strengths and weaknesses form only a part of the overall evaluation process. Glasson et al. (1994) evaluated various methodologies on the basis of the following factors:
1. Regulatory compliance;
2. Comprehensiveness of coverage;
3. Ability to bring out completely the nature of impact (short or long-term, permanent or reversible, positive or negative impacts, etc.);
4. Ability to identify and measure indirect impacts, cumulative impacts, etc.;
5. Ability to distinguish between significant and insignificant impacts and ability to measure significance;
6. Adequate provision for selection of preferred alternative by comparison based on unambiguous criteria; and,
7. Possibility of comparison against carrying capacity.

This study is oriented towards assessing impacts on the ecosystem for which EIA may be considered to comprise the following two subsystems (Norton 1984):
1. assessments of likely changes in the physical environment, the biotic component, ecosystem morphology and size.
2. effects of these changes on the valued ecosystem components namely, environmental quality, productivity, species composition, ecosystem behaviour and landscape characteristics.

Opinions of EIA scholars, on what should be expected from a complete EIA system, vary widely. An important source of disagreement is the inherent problem associated with the prediction of impacts. Certain commonalties in the criteria selected by various authors can, however, be noted (Atkins 1984). Previous chapters contain scattered presentation of expectations from an EIA system. A synthesis of observations by various authors leads to the following criteria for evaluating the effectiveness of an EIA system:

1. Ability to accommodate multiple objectives (which may at times be conflicting in nature) of decision making;
2. Provision of an appropriate screening subsystem to identify projects with significant environmental impacts;
3. Provision of scoping to identify important activities and environmental parameters to be brought within the realm of EIA analysis;
4. Provision of unambiguous criteria for comparison of alternatives;
5. Ability to take into consideration interactions among various direct impacts and to assess second and higher order impacts by evaluating the synergetic, potentiating and compensating effects;
6. Identification of beneficial and adverse impacts, temporary and permanent impacts, short-term and long-term impacts, reversible and irreversible impacts;
7. Evaluation of both significance and magnitude of impacts;
8. Incorporation of assessment of uncertainties, risks and associated hazards;
9. Consideration of ecosystem behavioural pattern under induced (likely) stresses and shocks;
10. Identification of surveillance and monitoring requirements during various phases of project life, namely, construction, operation, closure and post closure periods;
11. Separate assessment of impacts during each phase of project life without any trade-off between impacts occurring over different phases of project life;
12. Efficient communication of impact assessment results to decision-makers;
13. Linkages to regional assimilative capacity at criteria (4) through (11); and,
14. Fulfilment of the objectives of the project activities.

In addition to satisfying the requirement of environmental sustainability, the criterion 13 also helps comparison of fundamentally different and difficult to compare alternatives. Atkins (1984) suggested thirty points for evaluation of EIA methodologies. The factors suggested by him satisfy twelve of the thirteen criteria listed above. Atkins (1984) carried out theoretical evaluation of six EIA methodologies and found that BEES and Sorensen Network were satisfying only about half of the 30 criteria.