An assessment on the changing status of urban green space in Asansol city, West Bengal

Abstract

Urban green spaces play a crucial role in maintaining the sustainability of a city with the promotion of essential ecological functions to supplement the natural and social environment of the urban area. Preservation of a substantial proportion of the city’s space under green cover has now become a qualification for city planning and design. But the urban green spaces are vanishing out at an alarming rate caused by rapid and unplanned urbanization—especially in India. It has posed serious threats to the ecological equilibrium of the metros. The present study strives to explicate the spatiotemporal dynamisms of green areas in industrially reliant Asansol city as a corollary of its lopsided expansion during the past years. Though more than half of the study area (55.66%) is covers with vegetation, with notable per capita green space of 44.76 m2/city dwellers, but only 0.12% area in the core region of Asansol city is occupied by green cover with a negligible amount of per capita green space of 0.27 m2/city dweller, which is much lower than the international standard. Hence sharp discrimination in the distribution of green space has been observed between the city core and the peripheral region. Land use/land cover (LULC) map (2000 and 2018) and normalized difference vegetation index (NDVI) of the same years have been prepared to attest the land transformations in spatiotemporal context. The alterations consequent upon the surface temperature has also been appraised through land surface temperature (LST) maps of 2000 and 2018. A drastic change in LULC mosaic with vast destruction of green spaces (from 66.25 km2 in 2000 to 20.41 km2 in 2018) and increasing built-up and commercial spaces has been experienced over the last 18 years (2000–2018). Hence, nearly 14% of vegetated land has vanished during the observation period. Besides, a sharp increment in LST (both the maximum and minimum) has also been found during the stipulated period. The negative relationship between NDVI and LST reveals that the disappearing green spaces act as one of the active factors of increasing temperature during the study period, which has intimidated the sustainability of the natural as well as the social sphere of the city.