As the global temperature rises, Urban Heat Island (UHI) impacts are slated to enhance in the cities due to temperature increase. The informal settlement dwellings, constructed of heat-absorbing materials, having poor ventilation, and located in neighborhoods with a lack of green and open spaces, are more vulnerable to heat than the formal housing settlements. Rising temperatures are expected to adversely impact the health of the population in general and of the dwellers of the informal settlements in particular. While replacing the entire informal housing stock with formal housing requires stupendous costs, modifying this housing through introducing cool roofs is an interim physical adaptation solution to mitigate the heat impacts. The objective of this exploratory study is to assess whether built environment characteristics, with emphasis on cool roofs introduced in dwelling units in the informal settlements in Ahmedabad City in India, have improved thermal comfort within these dwelling units and, if so, whether this intervention has translated into mitigating health impacts of heat. The study reveals that the cool roofs have reduced temperatures within the dwelling unit by 1 ℃ to 1.5 ℃ during peak summer days. But other built environment characteristics such as cross ventilation, ceiling height, trees adjoining the dwelling unit, and open space in the neighborhood too have contributed toward reducing indoor temperatures. Adaptation to high temperatures in the informal settlements requires localized, doable solutions in the immediate term.