The Urban Heat Island Problem of Greater Kolkata, India

Abstract

Kolkata, a major metropolitan area in India, is vulnerable to the Urban Heat Island (UHI) effect due to rapid urbanisation and industrialisation. The city’s geographical and climatic conditions further exacerbate this phenomenon, resulting in significant impacts on the urban climate and public health. The UHI effect reflects the influence of climate change and human-induced stress on the natural environment, resulting in adverse health outcomes and higher energy consumption. This study examines the role of urban design and planning in contributing to UHI formation. It highlights the importance of integrating green infrastructure and energy-efficient solutions to reduce its effects. Landsat-9 Level-2 Surface Reflectance and Thermal Infrared Sensor (TIRS) data were used to analyse UHI patterns and vegetation dynamics through indices such as the Normalised Difference Vegetation Index (NDVI), Normalised Difference Built-up Index (NDBI), Land Surface Temperature (LST), and a standardised UHI Z-score. LST was derived by converting the thermal infrared band to brightness temperature and applying emissivity correction. The results showed clear temperature differences between urban and rural areas, with certain regions experiencing strong UHI effects. The rise of the average temperature of 4.4 °C highlighted the need for improved urban planning and the use of green infrastructure to reduce the negative impacts of UHI. Recommendations are the construction of Green Mark commercial buildings, skyrise greenery, gardens, and national parks to reduce building-related environmental damage. Incorporating these measures into current planning and construction practices to support micro-climatic improvements in the Kolkata metropolitan city that contribute to its sustainable development.