Caroline Knowles
5 min readJan 6, 2022


Sustainability and Indoor Air Quality in Bengaluru

Caroline Knowles

Bengaluru street scene

The air quality inside people’s living and work spaces has a significant impact on their comfort, productivity and wellness. Indoor air quality can be up to ten times more polluted than outside[i] and yet it doesn’t raise the same kinds of concern among those concerned with environmental pollution. It should. In urban areas people spend up to 90% of their time indoors[ii]. Building materials are one of the most important factors determining indoor air quality, particularly moisture, and earth building is more sustainable than concrete. Laboratory and field trials, jointly conducted by the University of Bath in the UK and the Indian Institute for Science, Bengaluru, in India, funded by the British Academy under its GCRF Urban Infrastructures of Well-Being Programme, are testing building materials for their ability to regulate indoor moisture and wellness[iii].

Stabilised earth bricks

Moisture has a significant bearing on indoor air quality and can act as a carrier for various pathogens and toxicity, as well as impacting a building’s structure, its durability, acoustics, odours, and aesthetics. Too much moisture can aggravate deterioration in buildings and accelerate the development and spread of contaminants impacting people’s health and wellbeing. Too little creates breathing difficulties, as well as skin and other irritations. This research tests different kinds of building materials for their ability to regulate indoor moisture by a process called moisture buffering. Moisture buffering is about how building materials absorb and release moisture in response to the moisture content in the air, thereby providing a degree of moderation.

Bengaluru is a growing metropolis of 12 million and India’s technology capital. Here, as in other cities, building is a persistent activity, and building for health is imperative, making Bengaluru is an important laboratory for testing indoor pollution. Researchers are testing traditional vernacular adobe buildings made from earth and lime, later vernacular adaptations, and what are now regarded as conventional buildings made from concrete. Emerging data clearly shows that traditional vernacular mud and lime construction houses have the ability to maintain optimum indoor moisture conditions and the healthiest environment for people to live in. Vernacular buildings are also better for thermal comfort, an important consideration with an increase in weather patterns associated with global warming.

Traditional earth building
Conventional cement building
Mix of vernacular and conventional building

The research’s social survey data shows that many people are content with earth-built houses as sympatico with the ways in which they live; others in contrast equate concrete and air conditioning with modernity and aspiration. But this association between concrete and modernity could change. In the Ghanaian capital Accra, earth brick building, often painted in attractive colours is gaining popularity with the affluent middle class[iv]. Good ideas and building practices travel: there is also evidence of growing interest in earth building in the Netherlands and in Germany because of concerns with indoor air pollution and sustainability and this may already be spreading to other parts of Europe.

Lab at the Indian Institute for Science, Bengaluru

Earth building is more sustainable than concrete: it has a low carbon footprint, not least because it is local, and affordable for low income communities. Researchers involved in this project suggest that earth-building can considerably reduce CO2 emissions. Sustainability is now an imperative, particularly given India’s position in the global production of greenhouse gasses and binding pledges to move to net zero. City authorities and activists often take a practical, on-the-ground, lead around precisely these kinds of issues, and provide the traction that is often lacking in international declarations of intent such as COP26 and its predecessors.

End of life PV building

When it comes to sustainability, Bengaluru is a city-wide laboratory for ongoing discovery and innovation. The lab at the Indian Institute of Science is also experimenting with using decommissioned solar panels as building materials. These panels are dumped as waste once their output is no longer economically viable. But the architects and scientists at the lab say they still have a 20–30 year life in producing small amounts of electricity, enough to charge phones and run wi-fi access points and small appliances. They are experimenting with ways of combining earth building and solar panels safely as building materials, turning the panels into roofs and walls in low income city settlements in need of energy and materials from which to construct informal — sometimes referred to as slum — houses and workshops. This could become mainstream for urban dwelling.

Caroline Knowles is Professor of Sociology at Goldsmiths University of London and Director of the British Academy’s GCRF Urban Infrastructures of Well-Being Programme. Caroline writes about migration and circulation of material objects — some of the social forces constituting globalisation. She is particularly interested in cities, having done research in London, Hong Kong, Beijing, Fuzhou, Addis Ababa, Kuwait City and Seoul.

[i] UK Royal College of Physicians and Royal College of Paediatrics and Child Health.

[ii] This often quoted figure is not broken down according to place, culture etc, possibly originating in US data.

[iii] This research is funded by the British Academy under its GCRF Urban Infrastructures of Well-Being Programme. Daniel Maskell at the University of Bath leads the research in collaboration with Monto Mani at the Indian Institute for Science, Bangalore.