I think you need to be careful when employing these words, the term sustainability has been employed left, right and centre and applied to everything, every concept, especially when companies are trying to "green wash" their image, when actually it has a very clear definition.
Sustainability is defined through the Triple Bottom Line approach which consist of positive environmental, social and economic impact. Only when a company achieve all three, it can be named as sustainable. If a business focuses only on the environment, then it is environmentally friendly, if it focuses on social aspect, then it is socially preferable
Social sustainability is of the three pillars of sustainability including environmental and economic aspects. When talking about social aspect of sustainability, you need to consider how a product/service/business is contributing to the local society (where the business is operating) or in general the social impact of business operations on planet earth.
A lot of tools can be employed depending upon area under research, in general the UN has provided generic metric to assess the social aspect of sustainability (link:https://www.unep.org/resources/report/guidelines-social-life-cycle-assessment-products).
I presume you are looking to assess social sustainability in India, i think this link:https://www.oxfamindia.org/resources can be helpful too (if not some research is needed from your side).
Third part of question measuring social development in terms of ecological perspective could be tricky and require more info and research, generally you can see the correlation of 'already established good practices' and your social evaluation of sustainability development. Best of luck.
Great question! The social branch is the most tricky one, since anyone who is engaged in improving social sustainability, does so following strong value judgements, therefore such projects are very much manipulated to fit a political agenda. This is neither good nor bad, just something to bear mind that it is always up to contestation. Another characteristic is that it mixes personal and interpersonal performances, the former comprising of areas such as health, education, different kinds of security, the latter including social cohesion, justice, communities etc. Here is our short paper talking about the peculiarities of social sustainability in the context of area development: Conference Paper Six Lessons Learned by Considering Social Sustainability in ...
The ecological perspective is really pertinent, since SocSus mostly has a human-centred perspective. You have to live with committing to certain ethical foundation, for instance the Seva paradigm that asserts responsibility for humans to serve nature rather than to exploit it sustainably. In another project we have established the "right to ecological space", a specialzed case of environmental justice which builds a conceptual framework and evaluation methods based on an interpretive literature review which might give you some ideas: https://justnatureproject.eu/resources/https-justnatureproject-eu-resources-public-deliverables/d2-1-report-knowledge-base-action-framework-low-carbon-high-air-quality-nbs-potentials