Urban sprawl eats into green cover over 20 yrs: City’s surface heat surges to 52°C

Nagpur: Nagpur's land surface temperature (LST) has risen dramatically over the past 21 years, climbing from around 35°C in 2005 to nearly 52°C in 2025, highlighting the growing impact of rapid urbanisation and shrinking green spaces on the city's microclimate.A comparative analysis of land use, vegetation and temperature patterns between 2005 and 2025 was done by scientist Shalini Dhyani, head, centre of ecological systems and resilience design, at CSIR-NEERI.On the eve of World Environment Day, the study reveals a strong link between expanding built-up areas, declining vegetation and rising surface temperatures. The findings raise fresh concerns over increasing heat stress, energy demand and the long-term sustainability of urban growth in the city.The study shows that Nagpur's built-up area nearly doubled during the period, increasing from 70.27 sqkm (34.72%) in 2005 to 140.53 sqkm (69.43%) in 2025. Large tracts of open land and vegetated areas were gradually converted into residential, commercial and infrastructure projects, making built-up land the dominant land-use category across the city.The loss of greenery has been particularly significant. Vegetation cover, which accounted for nearly one-fifth of the city's area in 2005, witnessed a steady decline over the years. While green cover stood at 43.27sqkm (21.39%) in 2015, it dropped sharply to 19.61 sqkm (9.69%) by 2025, indicating the erosion of natural cooling zones that help regulate urban temperatures.The assessment's normalised difference vegetation index (NDVI) maps further reinforce this trend. In 2005, Nagpur had extensive patches of moderate-to-high vegetation cover. By 2015, these green areas had become fragmented due to rapid development, and by 2025, most parts of the city exhibited low-to-moderate vegetation values, reflecting a continuous decline in ecological resources and urban green spaces.The temperature maps reveal a parallel transformation. Areas with vegetation and water bodies recorded relatively lower surface temperatures in 2005. However, warmer zones expanded significantly by 2015, particularly in rapidly urbanising pockets. By 2025, high-temperature zones had spread across much of the city.Dhyani attributed such warming trends to multiple factors, including the urban heat island effect, loss of tree cover, increasing vehicular movement, higher energy consumption, reduction in permeable open spaces and broader climatic changes. Although water bodies remained relatively stable, their share declined marginally from 0.75% in 2005 to 0.63% in 2025. While regulatory protections have prevented major losses, concerns remain over encroachments and the shrinking cooling influence of aquatic ecosystems."LULC, NDVI and LST analyses present a clear picture. Nagpur's rapid urban expansion has come at the cost of vegetation and open spaces, intensifying the urban heat island effect and pushing surface temperatures to alarming levels. The findings underline the urgent need for sustainable urban planning, protection of green spaces and large-scale afforestation measures to mitigate future heat risks," Dhyani said.