Angshuman Swargiary and Parijat Borgohain
Abstract
In India, the brick industry is classified under the âOrangeâ category, which indicates a moderate level of environmental impact. Brick industrial pollution is mostly in the form of suspended particulate matter, increased surface water turbidity, low dissolved oxygen levels, loss of topsoil and many other physiochemical damages to the soil. It is, therefore, essential to monitor the effects of brick kiln operations, especially those established in rural and suburban areas, to ensure that rural economic development is in balance with environmental sustainability. GIS-based environmental indices such as Land surface Temperature (LST), Normalised Difference Vegetation Index (NDVI), and Normalised Difference Builtup Index are essential for such purpose. In the present paper, a temporal analysis of the changes in the values of these indices over 20-year period, from 2005 to 2025, was conducted for the study area, including a correlation-based analysis of their inter-relationships. Spatial autocorrelation and hotspot analysis of the LST gave an idea about the changing thermal characteristics of the region. A field-based assessment quantified Particulate Matter (PM) along distance gradients from the kiln center. A rise of 5 °C in mean LST has been witnessed, which is a significant rise considering the rural nature of the landscape. While builtup index indicate growth in built-up areas, the negative mean points to limited development and selective industrialisation. Moisture index indicates increased local dryness while NDVI shows slight increase, likely due to compensatory greening efforts by the locals. PM levels measured along distance gradients from the kiln center provides a direct field-based indicator of kiln related pollution, its spatial concentration, as well as decay from the source.