DETAILS OF THE STUDY
Five building types – high-rise open housing and mid-rise open housing occupied by high- or medium-income groups of the society; low-rise open housing developed by Mhada, mid-rise compact housing constructed by SRA and low-rise compact housing comprising slums – were chosen for the study. The study classified heating hours from 12pm to 2pm; cooling hours between 6pm and 8pm. But temperatures during heating hours and cooling hours were different for each building type The highest rate of cooling at 5.5 degrees Celsius was recorded
which acts as a double jeopardy in terms of carbon emissions and energy security,” said Bardhan. “We wanted to suggest policy variables for urban development; meaning what building type minimises UHI effect within city.” Three building types (Mhada, high-and-middle income groups) were found to have a proportional distribution in terms of cooling zones nearby in the form of green spaces and water bodies that draw the heat and bring down temperatures, and heating zones such as pavements and parking spaces.
The analysis showed that slum-dwellers got more relief from the heat during the evenings than those living in SRA buildings. SRA buildings and slum areas lack green spaces, and therefore trap heat for longer duration, which radiates during cooling hours of the day. in a Mhada building where the mercury dropped to 25.8 degrees Celsius during cooling hours from 31.3 degrees during heating hours. SRA building logged the lowest rate of cooling at 1.2 degrees.
Based on the findings, the study has recommended policy makers provide real estate developers with a formula or a proportion on the mandatory distance required between buildings instead of a ‘minimum distance’ as mentioned in the existing development control rules.
“The challenge with Mumbai, however, is that majority of residential constructions are redevelopment projects, and therefore the distance between buildings cannot be changed,” said Avick Sil, regional director, Environmental Policy and Research India, who was not involved in the study. “Therefore, building arrangements need to be designed in a manner where there is cross-ventilation, appropriate sunlight and wind movement that will mitigate UHI effects by reducing energy consumption and emissions.”