Tanmay Tathagat is one of the leading energy experts in India who started Environmental Design Solutions (EDS), a multidisciplinary firm dedicated to the cause of sustainability in the built environment. Tathagat’s expertise lies in designing policies on energy efficiency, building energy simulations and integrated design. He is currently working on projects related to climate change mitigation policies, energy efficiency market transformations, sustainable city research and deployment, building code developments, energy-efficient building designs and net-zero developments. He spoke to Bhawna Jaimini on the pros and cons of Green building rating systems, the need for context-specific research and facing the mammoth challenges of saying no to air- conditioning consultants.
BJ: You have been working in the area of Green buildings for over 20 years. How would you
assess the impact of Green buildings, as we have come to define them today, on driving
actual sustainable development?
TT: The general awareness about Green buildings has definitely increased, but whether this has led to any
‘sustainable’ development is difficult to assess. I can’t really say that the mainstream construction practices
have changed, or their environmental impact has reduced. It is tough to make an assessment, especially in a
country like India, where we don’t have any standardised baselines to compare a before and after scenario.
Green building rating systems only talk about the number of buildings certified or savings achieved in those
buildings, we have yet to see an independent assessment of their real impact on the environment. A definite
answer to this can only emerge if some empirical studies are done.
However, the intent and awareness of Green buildings is on the rise. The number of certified Green buildings is
increasing exponentially every year, but I feel it has yet to have an impact on developers or the majority of the
construction sector, which happens in residential areas and outside the metros. So the owners and developers
have been misled into thinking that getting a certification is all that is needed to make a building Green. Actual
sustainable development will only happen when building design and construction, transportation, urban design
and infrastructure development are all looked at holistically, and the environmental impact of each decision is
considered in the process.
BJ: After working on developing Green building rating models for agencies like LEED and
GRIHA, do you think there is a successful model for a developing country like India, where
only a small fraction of population has access to architects and designers?
TT: Rating systems are only a part of the solution and we still have a long way to go in developing other models
that can cater to the diverse context of a country like India. Right now, the number of buildings rated Green
is roughly 2 to 3 per cent of the total construction done, starting from tier-three cities to big metropolises.
Buildings have a strong aspirational value and the rating systems have somehow tapped into it. We see that
individual owners are applying for ratings too. The scope and impact of our rating systems, though, is still quite
narrow because the approach is still based largely on international practices. But I am hopeful that it will evolve
in the future to be more contextual to how most of the country lives and builds.
The rating systems have brought in the aspirational value to Green buildings, and we can see developers
who typically do not care about environmental impact being drawn to it because Green ratings now have a
marketable value. The certification systems also now have a very strong social component, which pushes
developers to follow better health and safety standards, and provide better living arrangements to construction
labour. In our country, where labour is treated so poorly, this has helped to impose some checks and balances at
least in that small number of projects.
So overall, rating is a good idea because it sets a framework for evaluating and reducing the impact of
construction, and more importantly, engages with the people who own, develop, live or work in these buildings.
The rating systems, however, need to be holistic and contextual, and not end up being checklists for getting a
BJ: Like you said, the rating system has become aspirational but it is still quite narrow in its
approach. For example, while one building may be awarded the highest rating for using very
little steel and cement in an urban area, there are many buildings in rural parts of India that
do not use any steel or cement but are not rated at all. How do we deal with this gap?
TT: Ratings in India are not contextual in that very sense because we still have traditional construction
techniques and materials alongside steel, concrete and glass. A rating system can still be developed that looks
at the final environmental impact of each one while recognising the relevance of each typology. There are a few
rating systems globally that are looking at resource use in this way. In Japan, for example, the CASBEE system
rates a building along two parameters of environmental quality and loading, concurrently. The best buildings provide the highest quality at the lowest environmental loading. For example, if you are looking at thermal comfort, a fully air-conditioned building might score high on comfort but will be low on the energy-use scale. At the same time, a building with passive cooling methods might have a lower score on comfort but will be much higher on energy efficiency. In this way you can even compare with a passive building and often get a better rating. We need to develop a model along similar lines for India, which will enable rating systems to be relevant for more people and the way we design, build and operate our buildings.
BJ: A critique that often comes against the concept of Green buildings from your
contemporaries is that Green buildings justify consumption. A five-star rated air-conditioning
system does not change the fact that a building relies on air-conditioning. Do you agree?
TT: Absolutely. A lot of it comes from the way we present the information about environmental impact of a
building. You would find Green-rated buildings that claim to offer 40 per cent energy savings, which is great,
but the building still uses a lot of energy in absolute terms, and could even be more energy-intensive than
other non-rated buildings. This way of presenting figures comes from the West, where there are standardised
homogenous benchmarks against which such figures are easily comparable. In India, we don’t have such
references, so when we talk about 40 per cent savings, it is easy to be misled. A better way to evaluate would
be to state the actual energy use, for example, and not in terms of savings with respect to a hypothetical
This has been tried to some extent with the GRIHA rating for large developments, where the baseline is set at
net-zero impact. So, instead of presenting information as savings with respect to a notional consumed value,
the rating presents the real impact. No construction can have zero impact in reality, thus, by setting that as
a reference level, one can strive for minimum possible consumption. So, the Green building in itself does not
encourage or justify consumption, but the way environmental impacts are assessed or presented are not ideal,
and can often be misleading.