Data jam studies heat islands in Mumbai

MUMBAI: The next time you're sweating it on a hot and muggy day, take a look around. The aim of this exercise is to determine whether you are positioned in a 'heat island'.
'If you think the temperature on IMD's site does not reflect what you're experiencing, it could be because of your location and the impact of urban heat,' said a presenter at Mumbai 'Datajam on Urban Heat in Mumbai' at St Xavier's College on Saturday.
The data jam was organised by Open City, an urban data portal, along with NGOs such as C40 Cities, World Resources Institute India and Maharashtra's State Climate Cell. For seven hours on Saturday, more than 30 people including students and professionals assembled to study the effects of urban heat and how to tackle it.
According to the United States Environmental Protection Agency, urban heat islands form when some areas experience hotter temperatures than others within a city.
The participants at the data jam worked with data sets and maps that reflected land surface temperatures, demographics, formal and informal settlements, the morphology of buildings and other related elements in each civic ward in Mumbai – with a view to identifying heat islands, reasons and solutions. The civic wards focused on most were the ones that topped the list in vulnerability assessment done for the Mumbai Climate Action Plan (MCAP).
Slum areas formed the largest heat islands in Mumbai, owing to lack of ventilation and population density. But, the participants found, this phenomenon extended to some mid-rise buildings, which created a wind tunnel and trapped heat.
Interestingly, in H East ward, 70% of the population is crammed into 10% of the land that forms the slum pockets in Bandra East. This 10% land traps high amounts of heat, where temperatures range from 43 to 48 degrees Celsius.
Similarly, in the Bandra-Kurla Complex, which is spacious and ventilated, the glass buildings are the heat traps. Moreover, H East ward has little or no healthy vegetation.
M-East ward (Govandi), which ranks low on socio-economic factors, was divided according to the morphology of buildings and type of settlements. Participants highlighted that the BARC residential area was the only ideal spot in the ward, with low-rises and low population density.
'While several slum rehabilitation buildings are planned in the area, the height, density and construction material should be considered in terms of thermal conductivity. The ideal would be mid-rise and mid-density,' said Varun Phadke, a second-year MTech student at IIT Bombay.
Participants working on L ward (Kurla) suggested natural coolers and heat-resistant pavements as mitigation measures in the long term, more air-conditioned buses, and water filters at the bus stops. They also said that the Mithi River traps heat due to stagnant water and pollution, so cleaning it would act as a cooling agent.
These suggestions will be further presented to the ward officers and the state climate cell. The Maharashtra state climate cell undertook the development of a heat-resilience framework, which aims to look at local wards on a granular level for heat mitigation.

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