A sustainability assessment framework for high-rise residential projects: a case of India

Abstract In India, the polarization of growth towards urban areas leads to a considerable rise in multifamily, high-rise residential projects. Hence, incorporating sustainability in high-rise residential construction is one of the key aims of sustainable urban development. This study presents a comprehensive framework for the sustainability assessment of high-rise residential projects in India, addressing economic, environmental and social dimensions throughout the project’s life cycle. The proposed framework comprises 44 attributes, 11 criteria and three dimensions of sustainability based on an extensive literature review, Indian government policies and guidelines for environmental clearance of residential projects and India’s commonly adopted green building rating systems. The present study has identified 12 economically favourable sustainability attributes which can be helpful to encourage developers to implement them. Further, the analytic hierarchy process was used to evaluate the weights of identified sustainability attributes, criteria and dimensions based on experts’ opinions. The developed sustainability assessment framework provides a blueprint for promoting sustainable practices in high-rise residential construction. It can also be used to develop a sustainability assessment tool for high-rise residential projects.


Introduction
Real estate is one of the most vital sectors of the Indian economy, and it is expected to reach a market size of US$1 trillion by 2030, accounting for 18-20% of India's GDP (IBEF India).It is anticipated that the country will reach over one million in 68 cities, over four million in 13 cities and six megacities with a population of at least 10 million by 2030 (Ministry of urban development, Government of India).A significant increase in high-rise residential projects is expected to address this demand.Thus, the inclusion of sustainable practices during high-rise residential construction due to its mega-scale application becomes the top priority for countries seeking to progress sustainably.
Previous studies have proposed a variety of strategies for enhancing the construction industry's sustainability, including greening project management practices, green process innovation in construction methods, promotion of green building technologies, lessening energy consumption, greenhouse gas emissions and the release of waste materials, etc. (Yu et al. 2018).Most of the efforts mentioned above have focused on improving single or multiple construction project activities, due to which their impact on the overall project was quite limited.Sustainability enhancement requires a systematic understanding of implementing strategies, considering different phases of the project life cycle, which can impact overall project performance.Adopting sustainable policies is still in the preview of mandatory corporate social responsibility (CSR) initiatives.Unfortunately, sustainability implementation has yet to be a mainstream emphasis of the construction business.The main reason behind it is the cost associated with sustainability implementation, the difficulty of upgrading and synchronizing design processes with sustainability, and the safety issue (Akadiri et al. 2012).Mateus and Braganca (2011) and Zhang et al. (2011) recommended building sustainability evaluation and benchmarking methods to make the built environment more sustainable.
In India, the reference for green building assessment is a combination of codes and standards found in the state by-laws, the national building code of India (NBC), the energy conservation building code (ECBC), norms and standards for environmental clearance of large construction projects prescribed by the ministry of environment forests and climate change (MOEF&CC), Government of India and the criteria prescribed by the different green building rating programs.Today's preferred methods for evaluating the environmental performance of construction projects in India are primarily qualitative based on specific predefined requirements and criteria such as Leadership in Energy and Environmental Design (LEED) proposed by the US Green building council (USGBC), the GRIHA rating system proposed jointly by Griha Council and The Energy and Resource Institute (TERI), and the IGBC Green Homes Rating system proposed by Indian Green Building Council (IGBC).
The existing Green building systems and environmental standards may cover some aspects of sustainable construction (SC): however, green and sustainable may have substantial distinctions, with the former focusing on the environment (interior and outside) and occupant comforts while the latter spans a more comprehensive array of the economy, society and environment (Chong et al. 2009).Integrating economic and social needs while assessing the sustainability of a project has received less attention.Addressing sustainable development objectives demands a comprehensive strategy based on a three-tier approach considering the local context.Further, the green rating tools have been primarily focused on the design and operation stage of the project lifecycle, and the execution stage of the project has received little attention.Therefore, practical and sound implementation of green concepts, especially addressing the execution phase of projects, represents the actual challenge of the construction industry (Forbes et al. 2002;Cha et al. 2009).
The assessment methods developed for one country may not be suitable for others due to variations in site conditions, geography, climatic conditions, resource consumption level and public awareness.Hence, it is not feasible to use existing tools like LEED to assess a building's performance in India (Suchith et al. 2019).Vyas and Jha (2016) and Reddy et al. (2018) created a building evaluation system based on the Multi-criteria decision making (MCDM) method and the perspectives of several construction industry stakeholders in the Indian context.
The existing green building rating tools and approaches primarily focus on environmental needs, whereas economic and social issues were always given second priority during the assessment.On the contrary, from the developers' perspective, the economic benefits of sustainability implementation are more attractive compared with environmental and social dimensions.Considering the limitations of the sustainability approaches mentioned above, developing a holistic sustainability evaluation framework which can address all the phases of the project life cycle becomes essential.Therefore, the present study attempts to develop an integrated hierarchical system of attributes, criteria and indicators for the sustainability assessment of high-rise residential projects in India.It provides a comprehensive set of indicators addressing the planning, designing, construction and operation and maintenance phases of the project life cycle.The developed sustainability assessment framework may aid the firm in monitoring the sustainability status and accordingly planning the activities to enhance the sustainability of high-rise residential projects.

Research methodology
The research methodology (Figure 1) used for designing the sustainability assessment framework is divided into two stages.The first stage includes identifying and finalizing sustainability attributes, criteria and indicators.The significance of these finalized sustainability assessment parameters was analysed in the second stage by assigning weights to each parameter using the AHP approach given by Saaty (1980).

Research stage I: identifying and finalizing sustainability attributes, criteria and indicators
The attributes, criteria and indicators considered for developing the sustainability assessment framework are based on the study of the approaches adopted by earlier researchers and current practices for sustainability assessment in India.Global scenario of sustainability assessment Due to a lack of general agreement and well-defined sustainability attributes, the sustainability assessment is subjective.There are many national-level environment assessment methodologies, such as LEED in the US, BREEAM in the UK, CASBEE in Japan, GBTool in Canada, DNGB in Germany, GBAS in China and GRIHA and IGBC rating systems of India, etc.However, these methods usually focus on environmental performance and ignore sustainable development's economic and social aspects (Abdul-Rahman et al. 2016).Developing a sustainability assessment framework based on a three-tier approach to sustainability is essential to promote a more sustainable built environment.The earlier research related to sustainability enhancement in construction can be broadly categorized into three areas: identification of sustainability indicators, development of a sustainability assessment framework and promotion of sustainable construction practices.
Glavic and Lukman (2007) classified various sustainabilityoriented terms as a hierarchical system of principles, approaches, subsystems and sustainable systems applicable to real-world problems to promote a standard, unambiguous terminology related to sustainable development.Many researchers have presented different sustainability performance indicators to promote a more sustainable built environment.Hossein and Habib (2012) categorized sustainability into four groups: environmental, social, economic and technical.The objectives of these four groups include boosting financial savings, lowering adverse environmental effects leading to increased environmental compatibility, increasing social efficiency and usefulness and improving the quality and optimizing the construction process.Hussin et al. (2013) proposed several strategies for balancing sustainability's environmental, economic and social aspects.Ali et al. (2013) proposed 47 key performance indicators for company-level performance evaluation and management in Saudi Arabia.To improve the life cycle performance of residential construction, Tam and Zeng (2013) developed a set of sustainable performance indicators for Australian residential buildings considering the environmental, economic and social dimensions of sustainability.Lavy (2011) proposed key performance indicators for facility performance measurement based on financial, physical and functional aspects.Lufan and El-Gohary (2016) introduced a multi-scale analysis of sustainability indicators based on five criteria: relevance, specificity, reliability, scientific soundness, measurability and data availability.Stanitsas and Konstantinos (2021) presented indicators for promoting sustainability in project management practices.The framework developed by Sodangi M. ( 2019) provides different strategies for improving the practical adoption of sustainable practices based on three categories of enablers, i.e. institutional and economic enablers, project, client and end-user enablers and organizational enablers.Zulu et al.(2022) identified various drivers and enablers for sustainability implementations in the Zambian construction industry to help the practitioners to design methodology for sustainability implementation.The researcher outlined many techniques and approaches that can be used during the lifecycle of building projects.
In addition to the indicator identification, the researchers also used these indicators to develop a comprehensive sustainability assessment methodology for construction projects.Ali and Al Nsairat (2009) proposed a green building evaluation methodology for the Jordanian setting.Alwaer and Clements-Croome (2010) devised a way to evaluate intelligent buildings' sustainability.Wallbaum et al. (2012) developed a sustainability evaluation tool for low-cost housing based on different indicators.Akadiri et al. (2012) developed a conceptual framework for implementing sustainability addressing cost efficiency, resource conservation and human adaptive design.Chandratilake and Dias (2013) devised a rating system for Sri Lanka based on the AHP approach.Alyami Saleh et al. (2013) used Delphi Approach to design the sustainable building evaluation method for Saudi Arabia.Siew et al. (2016) proposed a sustainability assessment framework using a systembased approach for selecting and quantitatively measuring sustainability criteria.The research focused on distinguishing deliberate sustainable practices, criteria characterization using measures of central tendency and dispersion, and weighing and combining the criteria to get an overall sustainability score.Wirahadikusumah and Ario (2015) proposed a model to check contractors' readiness to implement sustainable principles for Indonesia based on a three-tier approach to sustainability; this provides guidance to adopt sustainable practices in premature construction industries.
According to a literature survey, researchers used many sustainability metrics and approaches to evaluate the sustainability of residential developments (Robichaud and  This comprehensive literature survey assisted in the identification of different sustainability actions addressing various phases of the project life cycle.It was also helpful in developing a sustainability assessment framework for high-rise residential buildings in India, considering the needs and concerns of different stakeholders.

Methodology for identification and finalization of sustainability attributes
Along with the literature review, the present study reviewed commonly used rating systems of India, i.e.GRIHA 2019, IGBC (2016) IGBC Green Homes rating system version 3.0 and LEED (2016) LEED v.4.1 for residential (BD þ C) and the recommendations of the National building code of India (NBC) 2016 to identify sustainability actions for high-rise residential projects.The sustainability actions were identified based on the three-tier approach of sustainability and a systematic understanding of various strategies and actions to be implemented during different phases of the project life cycle.A questionnaire with a five-point Likert scale was created to assess the significance of chosen sustainability actions.Before the actual survey, the initial questionnaire was pilot tested with experts and suggested modifications were incorporated.The potential experts for the questionnaire survey were selected based on their education, experience, position and role in directly handling all project life cycle phases of high-rise residential projects.The questionnaire survey was performed using a panel of 16 experts with 10 years of professional experience, including project managers, architects, consultants and academicians involved in higher education and research.The identified sustainability actions were rated by the experts using five points Likert scale, and the relative importance index (RII) was calculated for each sustainability action using equation (1) (Tam and Zeng 2013) where w denotes the weight assigned to each sustainability action by the experts ranges from one to five, with one being the least significant and five being the most important.A denotes the highest weight (A ¼ 5 in this study).N stands for the total number of samples.RII stands for relative importance index, varying from 0 to 1.
The sustainability actions with RII !0.7 were considered for framework development.The values of RII are used for the initial screening of the sustainability actions considered for framework development.These sustainability actions were further categorized into logical groups known as attributes based on their conceptual similarities using the affinity diagram technique.These attributes were then clubbed to form different criteria, which were finally linked with three sustainable dimensions leading to the development of a hierarchically structured sustainability assessment framework for high-rise residential buildings.Supplementary Material Tables S1 and S2 elaborate on the references reviewed for selecting sustainability attributes and their RII, respectively.The present study adopted a criteria decomposition approach, i.e. breaking down the criteria at lower hierarchical levels and forming a criteria breakdown structure, which helps to avoid overlapping the criteria.It also promotes pair-wise comparison of parameters at different hierarchical levels rather than evaluating the relative importance of too many parameters simultaneously (Siew et al. 2016).

Research stage II: finalizing the significance of sustainability attributes, criteria and indicators
The analytic hierarchy process (AHP) was used to finalize the weights of sustainability attributes, criteria and dimensions.Small sample size, high consistency level of judgement, simplicity and user-friendly software are the main arguments favour using AHP (Darko et al. 2018).It is a valuable method for weighing parameters at different hierarchical levels (Tupenaite et al. 2017), and it is a widely adopted weighing method by many researchers (Al-Harbi 2001; Kang and Lee 2007;Shapira and Simcha 2009;Darko et al. 2018).
The expert panel formed for the AHP study was comprised of nine construction professionals, including an architect, project manager, consultant, developers with !5 years of experience in managing high-rise building projects and academicians involved in higher education and research.Panellists were selected from industry and academics to ensure that the panel possessed both a practical and scientific perspective.A questionnaire was developed for pair-wise comparison of the different attributes, criteria and dimensions at different levels of hierarchy, and opinions were collected from the panel members.The panellists were not aware of the identity of the other panel members.
Although the participant replies varied in the early rounds of the Delphi procedure, the consensus was reached in the later rounds.The panellists were allowed to revise and amend their responses in light of the responses given by other panel members in subsequent rounds.In the present research work, three rounds of the Delphi study were carried out to achieve the desired level of consensus.Based on the evaluation of experts' opinions, individual weights were assigned to attributes, criteria and dimensions by forming pair-wise comparison matrices at each hierarchical level using Saaty's scale of pair-wise comparison.The different stages adopted during AHP implementations are listed below.
1. Identifying the problem and defining its objective.2. Development of a hierarchical structure by placing the goal at the top, criteria at intermediate levels and a list of options at the bottom.3. Development of a set of pair-wise comparison matrices for each level of the hierarchy.The pair-wise comparison was made in terms of the element preferred over the other using the relative scale of measurement shown in Table 1. 4. Evaluation of the weights of each attribute, criterion and dimension.5. Calculation of the consistency ratio (CR) to check the matrix's consistency.The CR was used to assess judgement consistency.It was calculated using the equation CR ¼ CI/RI, where CI is the consistency index and RI is the random consistency index which depends on the size of the matrix.Saaty's (1980) random consistency index (RI), as mentioned in Table 2.
The eigenvalue k max was used to calculate the consistency index CI using Equation (2): where n is the size of the matrix.
The recommended CR values for different sizes of matrices given by Saaty (1980): are 0.05 for three by three matrices, 0.08 for four-by-four matrices and 0.1 for larger matrices.
To measure the agreement of weights among the experts Kendal's coefficient of concordance (W) was calculated by using Equation (3): where m is the number of experts/evaluators; n, Number of alternatives to be rated; W is the Kendall's coefficient of concordance; T is the correction factor for tie ranks; S is the sum of squares of deviations of data point from the sample mean.
The significance of the concordance coefficient (W) was statistically analysed by v 2 , which has a distribution with a degree of freedom v ¼ n-1 calculated using Equation (4): Suppose the v 2 a, v > v 2 critical the significance of concordance coefficient exists on that a level, the agreement of experts' opinions is satisfactory, and group opinion can be established.Otherwise, when v 2 a, v < v 2 critical, it implies that the respondents' views are not in consensus and differ widely, due to which the rank's correlation hypothesis cannot be accepted.
The global weights of attributes obtained through AHP were used to rank the sustainability attributes.Supplementary Material Tables S3 and S4 elaborate on the raw data related to local and Random consistency Index (RI) 0 0 0.58 0.9 1.12 1.24 1.32 1.41 1.45 1.49 global weights and ranks of sustainability attributes, criteria and dimensions and their statistical significance based on the questionnaire survey.

Results and discussion
Based on the adopted methodology, including an in-depth literature review and current guidelines for sustainability assessment in India, 174 sustainability actions with a RII !0.7 have been identified for developing the sustainability assessment framework.
Of the 174 sustainability actions, 93 were found to be effective in the planning and design phase, 67 in the execution phase and 14 in operation and maintenance phase of high-rise residential projects.These sustainability actions were categorized into 44 groups based on their logical similarities and named attributes.The 44 attributes comprised 12 economic, 20 environmental and 12 social attributes.These 44 attributes were further merged into 11 criteria, finally linked with three sustainable dimensions forming a three-level hierarchical structure (Figure 2).The relative weights of identified parameters were measured using the AHP method, and the values of local weights of different parameters are mentioned in Figure 2. The global ranking of sustainability 44 attributes using AHP revealed 'wastewater treatment and management', 'promotion of sustainable building materials' and 'rainwater harvesting and water conservation measures' as the top three sustainability attributes, with global weights of 0.146, 0.109 and 0.076, respectively.Similarly, the global ranking of sustainability criteria revealed 'water efficiency' as the top prioritized criterion with a global weight of 0.242, followed by 'material and waste management' and 'construction process improvement' with global weights of 0.170 and 0.151, respectively.The prioritized attributes under 11 sustainability criteria linked with environmental, social and economic dimensions are discussed below.

Environmental sustainability dimension
The environmental sustainability dimension is the most preferred in the sustainability assessment.The present study reports five criteria and 20 attributes under this dimension.Among the five attributes listed under land use and control of environmental descriptions criteria (Figure 2), the panel of experts preferred three attributes, namely 'planning, monitoring and control of environmental descriptions' (0.286), 'promotion of sustainability' (0.239) and 'rainwater management' (0.186).Measures to minimize air and soil pollution during construction are mandatory appraisals in the GRIHA rating system and are also mentioned as a prerequisite for sustainable sites in the LEED rating system commonly adopted in India.
In urban areas, due to high water usage and complex consumption patterns within small but heavily populated areas, water resources are under severe stress.Thus, experts ranked 'wastewater treatment and management' (0.604) as the most important attribute in water efficiency criteria.
The increased energy requirements of high-rise buildings make 'Energy, fuel efficiency' one of the crucial criteria under the environmental dimension.Considering the key role of the building envelope in the energy efficiency of high-rise structures, the panel of experts selected 'building envelope optimization' (0.304) and 'energy efficiency for the building and systems' (0.209) as essential attributes under this criteria.Improvements in building envelopes, such as insulation, air sealing, and highperformance windows, lower heating and cooling loads and allow heating and cooling equipment to be downsized when paired with efficient ventilation.
Appropriate material selection plays a vital role in enhancing the energy-efficient design of buildings.The panel of experts prioritized the 'promotion of sustainable building materials' (0.643) under material and waste management criteria.This attribute includes green procurement policy, design optimization to encourage optimum use of construction materials and promoting the use of local building materials and alternate construction materials such as GGBS, fly ash, artificial aggregates, etc. Promoting effective organic waste management practices post-occupancy was ranked as a less important attribute as it becomes a mandatory requirement for all new housing projects to provide facilities for organic waste management and recycling.
The innovative strategies adopted at various levels of the project life cycle aids in sustainability implementation.Under these criteria, 'construction management practices for incorporating sustainability' (0.450) and 'promotion of sustainability during policy-making decisions' (0.444) were the experts' prioritized attributes.Innovative construction management practices and policy-making involve assessing site conditions before design, contractual obligations towards sustainability, choice of construction method to improve sustainability, the inclusion of sustainable construction needs in the feasibility report, etc.
The panel of experts ranked the 'waste water treatment and management', 'promotion of sustainable building materials' and 'rainwater harvesting and water conservation measures' as the top three attributes among 20 under the environmental sustainability dimension.
The panel of experts also ranked the five environmental sustainability criteria and prioritized 'water efficiency' (0.359) and 'material and waste management' (0.252), as the attributes covered under these two criteria were found crucial for enhancing the environmental dimension of sustainability.

Social sustainability considerations
Social sustainability in the present study includes stakeholder engagement, user considerations, diversity and inclusion during team formation, management considerations, health and safety, community considerations and contribution to the local economy.In the present study, the four criteria identified under this dimension agree with the social sustainability framework presented by Valdes-Vasquez and Klotz (2013).
Among the three attributes identified under accessibilities, neighbourhood and community considerations criterion, the highest significance was assigned to the 'access to basic amenities' (0.602).Similar findings indicating access to work opportunities and public transportation as top priority criteria under the social sustainability dimension were reported by Tupenaite et al. (2017).
The occupants' comfort criteria consist of 'adaptation of passive, active and low impact design strategies', 'improvement of indoor air quality', and 'promotion of positive social impact'.The panel of experts assigned the highest significance to 'adaption of passive, active and low impact design strategies' (0.652).The final energy use of a building can be profoundly affected by architectural design aspects such as building shape orientation and window-to-wall ratio.Passive design techniques are inherent aspects of a building's shape and design that channel natural resources to provide thermal comfort.Enhanced indoor air quality strategies promote occupants' comfort and well-being.Options for improving indoor air quality may include walk-off mats, filtration, enhanced local exhaust, air quality benchmarking, etc. Promoting facilities for the physical wellbeing of occupants, such as gymnasium, meditations or any indoor, or outdoor games, per capita availability of green spaces, bicycle facilities, urban agricultural practices, etc., can help create a positive social impact.
Apart from occupants' comfort, their economic benefits through design considerations and operation and maintenance protocol were evaluated using three different attributes.The experts ranked 'fundamental system testing and verification, occupants' economic benefits through design considerations' (0.681) as the most crucial attribute.This attribute focuses on the project's design, construction and operation that meet the owner's project requirement for energy, water and indoor environmental quality and durability.It also focuses on stakeholders' engagement throughout the project life cycle.
The criteria aimed at the social sustainability implementation during execution involved three attributes: 'provision of health and hygiene facilities for construction workforce', 'prevention and management of construction accidents', and 'promotion of local employment'.The experts assigned the highest significance to 'promotion and management of construction accidents, disaster risk mitigation plans' (0.566).The second priority was given to the 'provision of health and hygiene facilities for the construction workforce' (0.308).Accidents and fatalities lead to increased expenses and delays, which are detrimental to all parties involved.According to Gunduz and Khader (2020), the top three safety hazards in construction are a lack of a firm's safety policy, inadequate safety training, and failure to enforce, motivate, and train workers to use PPE.
Of the 12 attributes covered under the social sustainability dimension, the experts ranked 'adaption of passive active and low impact design strategies', 'fundamental system testing and verification, occupants' economic benefits through design considerations' and 'promotion of positive solar impact' as the top three attributes.
Along with the attribute ranking, the panel of experts also ranked the four criteria under the social sustainability dimension.The 'occupants' comfort' (0.611) was rated highest by the experts.

Economic sustainability dimensions
As stated earlier, due to economic constraints, sustainability implementation has yet to enter the mainstream focus of the construction business (Holloway and Parrish 2013).In the present study, the economic sustainability dimension has identified two favourable monetary criteria, (i) construction process improvement and (ii) market competitiveness comprising 12 attributes (Figure 2).
In the construction process improvement criterion, among the seven identified attributes, the panel of experts assigned the highest significance to 'process improvement techniques' (0.271), and the second priority was given to 'construction project management' (0.228) as the process improvement is the key to enhancing economic performance.
Market competitiveness is defined as a company's ability to provide better value, quality and service to customers than its competitors.The market competitiveness criterion involved the five attributes (Figure 2).The experts assigned the highest significance to the attribute 'design for durability' (0.415) followed by the 'cost of construction (affordability)'.The durability of a building is a prime consideration, especially when designing sustainable structures, and a long-lasting structure compensates for construction costs over a long period.Durability can also be linked with all three dimensions of sustainability and hence assigned the highest significance by the panel of experts.
Among the 12 attributes included under the economic sustainability dimension, the experts identified 'process improvement techniques', 'construction project management' and 'optimizing the performance of plant equipment and machines' as the top three attributes.
A comparative rating of two criteria under the economic sustainability dimension revealed that 'construction process improvement' (0.816) is more important than 'market competitiveness' (0.184).
Finally, the overall ranking of three key dimensions by the experts revealed that environmental sustainability (0.673) is most significant, followed by economic (0.185) and social dimensions (0.142).Different researchers in earlier studies also highlighted the higher significance of the environmental dimension.

Conclusion
The present study proposes a holistic sustainability assessment framework for high-rise residential projects in India.It comprised three levels: sustainability dimensions, criteria and attributes.The developed assessment framework will provide guidelines to stakeholders of high-rise residential projects to improve project performance throughout various phases of the project life cycle according to the principle of sustainability.The selection of attributes and criteria depends mainly on the RII and relevance to the local context.The experts' ranking of sustainability indicators using the AHP process revealed that in the environmental sustainability dimension, 'water efficiency' and 'material and waste management' are the top priorities of highrise residential projects in India.In the social sustainability dimension, 'occupants' comfort' was the most important criterion, followed by 'occupants' economic benefit through design considerations and operation and maintenance protocol'.Construction process improvement was the most significant criterion in the economic dimension.Global ranking of the 44 attributes revealed 'wastewater treatment and management', 'promotion of sustainable building materials' and 'water conservation measures' as the top three attributes, respectively.
According to a panel of experts, the environmental sustainability dimension is more significant than the economic and social dimensions in attaining sustainability objectives of highrise residential projects.The cost of implementing sustainability is a significant barrier, due to which sustainability implementation has yet to enter the mainstream focus of the construction business.In such situations, phase-wise achievements of sustainability criteria mentioned in the framework can help achieve more green credits on limited budgets.The focus of phase-wise implementation should be on specific attributes of the assessment framework depending on the firm's constraints, readiness for implementing sustainable practices and phase-wise goals and objectives to be achieved.Even though the sustainability assessment framework proposed in the present study is developed for the Indian context, the methodology adopted for developing the integrated framework may prove helpful for much broader geographical applicability.

Figure 2 .
Figure 2. The hierarchical structure of sustainability indicators, criteria and attributes with weights.